J.J.
hi M.;
i agree w the mom who said he's only 3.5 and not to expect perfect sharing too soon; HOWEVER; my adivce to you, having a 3.5 yr old boy also, and a 20 mo old girl is;
"1-2-3 MAGIC!"
this is a behavior correction system that is humane, simple, and absolutely works. it's by Dr. Phelan, a ped psychologist, and you can buy the book used on Amazon for like $8. the book is a fast and enjoyable read; we read it in two nights. and if you use the system 100% of the time, EXACTLY as the book directs, you WILL have great improvement in a week, i am not kidding.
when my son was about 32 mos till the summer he turned 3, he went through some terrible aggression and anger; hitting, pushing the baby, beating up older kids on the playground; he basically spent all his playschool time in time out; he was hitting us, screaming; horrible. we took him to a ped psychologist just to be on the safe side and the dr evaluated us and him for an hour; and he said to us that we have a bright, strong, charming child who has a lot of stress and that we have poor boundaries. in fact we had recently moved, which was stressful, my husband was working a lot of overtime, my son was getting very jealous of the baby, it was all very hard on him. and we realized that we were allowing a lot of our anxiety to filter down to our son.
the 1-2-3 system is NOT like random time-outs. it's very specific. it teaches you how to take responsibility as the parent, to take control of yourself and the behavior of your child, without apology or drama. this dr. had us buy this book and he coached us for about 3 weeks on how to use it. and our son's behavior turned around completely. we continue to use it with great success and plan to start it with our daughter when she turns 2.
you don't need a doctor to coach you tho; just read the book thoroughly as the book directs; start with the intro. and practice the system correctly. your son will thank you.
lots of luck,
J.