Have you ever taken parenting classes? I ask because I am a step-parent and I have my own biological child. I know both sides of the fence all too well. 3 years old is a very hard age and it's going to be even harder for him knowing that there's another lady that comes in and out of his life without consistancy. He's not going to understand what's going on. He's taking out his emotional frustrations on you and the family because he feels safe to do so. I know it's a frustrating place to be in yourself but just imagine what it's like to be in his little body and little mind when his biological mom comes around. there's going to be a huge amount of emotions and he's not old enough to know what to do with them. In all honesty, it's hard enough to put adult emotions in the proper places. My step-daughter is almost 7 and she stills acts out with anger towards us when she's having a difficult time at her mom's house. It's really hard to watch but I took classes on co-parenting and I'm a frequent visitor to step parenting web sites and they can really help. We stay away from punishing when she's visibly upset because we don't want to give her negative attention during these times. Part of the reason she gets so upset is because she's needing attention and if her mom can't give it to her than we get the fall out because she feels more safe with us. She already knows that we are always there for her and she uses that safety net when her other house isn't so safe. It is hard to be on the other end when it seems like all we experience is her anger, but at the same time it's an honorable place to be because she feels safe enough to be herself and show us how she's feeling even though she still can't put words to her feelings very easy. If you can step out of your body for just a minute when your step son acts out it might be easier to see what I mean. Give him love and affection. Hold him tight and tell him you know he's in pain and upset and you're there for him. 3 year olds don't need a lot of words, they just need love. Give more praise when he's acting appropriate to you and the acting out will lose some power in his mind. If he doesn't receive attention (even when it's negative) for a particular action, no matter how inappropriate you think it is, and he already knows he'll receive attention for what you consider good behavior, the good behavior will win out over the bad no matter what has triggered him. My son is 3 and I know all too well what they are capable of. It's a hard year but with a little extra love and affection, and trust me, there have been plenty of times when that's the last thing I wanted to give him, it really paid off. I know you said both you and your boyfriend work full time, but if you can both find 15-30 min of time when you come home to really give to him without tv, no phone, etc, that will also keep some inappropriate behavior at bay. Be careful when you move into "their" house as well. I would ask your boyfriend to talk to the older boy and let him know that he's not losing his house or his dad, and that there house is going to become your house as well. 3 year olds get very possessive over everything and that last thing you need is for his to have resentment towards you. Respect his space and make your move slowly if he's acting up or showing anger. You can't get these early years back and if all the attention he gets right now is when he's in trouble you're setting yourself up for a nightmare. Little boys need more love and attention to grow up into loving men than little girls do. Adults don't shower boys with attention as much as they do girls, but in my opinion they need it even more because of that. He's still just 3, not 6, not 10, not 16, and a lot of time (myself included) we adults can slip up and expect them to not have the same emotions that girls have. But that's not true. And they are going to have an even harder time out in the real world because of that perception. that's why in my opinion it's even more important for your house to be safe for him to express his emotions becuase it might be the only truly safe place he has. Remember too, even though you're the woman in his life, he knows that his biological mom isn't around. It's hard enough to understand that one as an adult so can you imagine how confusing it is for a little 3 year old to wrap his brain around that one let alone his heart? All he's going to wonder is why do I get to see this other lady? Who is she? Why do I feel like I know her but then again I don't? If this other lady drops in and out of my life without consistency is my dad's girlfriend going to do the same thing? Who's my mom and why can't she be in my life? Don't take anything personally. He's not trying to hurt you or his dad by acting out after he see's his mom. He's completely overwhelmed by everything and just needs pure and simple love. He needs reassurance that you and his dad are still going to love him even when he's acting out. You don't need to give him the wrong attention though. I simply tell my little boy that when he can calm down I'll listen to what he needs to tell me. I will turn off the tv, the phone, stop making dinner, etc during this time and just sit with him in silence while he's working through his emotions. It gives me time to calm down myself and before I know it he's a different kid again and our family life can get back to normal. This isn't his fault he's only 3. It's his fault if he's still acting out at 30. You're almost there yourself I think you can understand. what I mean by that. Trust me, I'm 32. I've been in your exact position with my step-daughter and I deal with my 3 year old boy and his emotions everyday. All I know is consistency does work and so does staying calm and talking in a very firm yet loving voice. Taking toys away, and constant punishment for bad behaviour only breeds more bad behavior. You don't have to accept what he's doing though. You need to lay down some ground rules that are non-negotiable and make sure you stay consistent with them. Give him a warning when you notice inappropriate behaviour. If he keeps it up than simply take him by the hand, in a calm assertive way, and remove him from the situation right away. Ask him if he knows why you did that. If he does, reward him with a hug or a smile, what ever works for you so that he realizes you're praising his telling the truth and his being aware of what you don't like, but still tell him he needs to change his behaviour. If he still does it than nothing is said and you remove him from the situation only this time you keep him removed by giving him an appropriate time out. It might sound like a lot of work at first , but my little boy responds to this right away. He knows if he gets me to the point where I'm not talking to him anymore he went way to far. He wants the love and attention and when I take it away he knows exactly why. I used to get really upset wondering why I had to go through all this extra work when I myself felt so overworked. I had someone remind me that raising kids only lasts for such a short period of time and that the rewards of knowing you raised a caring, loving child far outway any lost private time I might experience. and I'm seeing that with my step daughter. she's 7, and already I can see that our relationship is changing drastically. I'm thankful everyday, that I had the energy to really make sure I gave her a safe loving home when she was younger. You won't be rewarded for your efforts right now. You have to get over that as an adult. It still tears my heart out sometimes, but then I realize how much more I appreciate my parents or other adults that were in my life the older I get and it's reassuring to know that one day my kids will be my age and think of me with the same kind of love. You're his mom right now and you really owe it to him to give him the best you can and keep learning how you can improve because after 3 comes 5 and 8 and you will be constantly challenged. You think you understand him and the next minute it feels like you have to start all over again. It happens to all of us. If you truly want to be in these kids life make sure you are willing to give them all of you and all your time. If you aren't willing to do that, it's ok, I'm not judging you, you just need to be fair to them and leave their lives as soon as possible. It's very hard being a step-parent and it's only going to get harder if you have your own child with their dad. But with the right support and keeping your mind open to advice and to growing intellectually you'll be more than ok. I hope this helped.