3 years, yep that’s about right, she probably decided it was time to get married if they were going to continue the relationship, right now by making your child feel welcome this other woman can show your ex that she loves him and his child, witch will make your ex feel he is doing the right thing by marring her. Your forgiveness for your ex husband honors the relationship you once both shared and the child you had together. Blaming the other woman gives you the feeling you desire that she was the reason you and the child were abandoned by your then husband, the person who is supposed to protect the family at all cost. This together displays that you could have remained a couple and retained your dreams if it weren’t for this other woman’s involvement in the downfall of your family. Actually he probably hit on her, she probably wanted him but knew he was married so he convinced her the marriage was rocky. She probably was okay with it for a while then decided it wasn’t fulfilling enough and when she ended it with him he decided to go ahead and leave you. Now that your remarried I guess it just comes down to not putting blame were it belongs? Letting go of the hate that you feel for the other woman takes the blame off her and back on your ex, so I guess this is just the way you have decided is the best way for you to deal with what happen.