I have children myself....i totally understand your anger...maybe you are just angry about knowing he has someone new..but i think we just need to take a deep breath first and find out what's goin on before making any major changes. How old is your son? Anyway, we have to remember that sooner or later there will be a new person in the picture...and what you should be concern about is if this person is capable or trust worthy to treat your son the best way without putting him in between the attention...i am  in the process of separation myself and my husband is stressing out about if i am with someone new. As for my feelings, i wished he find someone new soon so he stop giving me shits about all his insecurity, over controlling , immature attitude..but i always hope that if he does get involve with someone new..i hope it's not a bitch that will make my childrens life difficult..if anything, i want to make sure she is good to my children and take away the love of their father...because in the other side if i get involve , i promise myself to be honest with my children first before bringing a new face in the picture..i just would be afraid of my husband's reaction if he finds out...so it's ok to be angry...but think about the childs feelings and find out how he feels about it or her i should say...but don't be negative that it will make the child confused..i'm sure he loves his father very much and want to be happy around him and as well as he would want his sons happiness too.

cookster, you are justifiably angry right now so don't make any rash decisions. Think about what is best for your son. What your ex did was wrong and quite inappropriate but he is your sons father. Get past the anger and hurt and figure out how your son can see his dad without the OW being there.

I feel for you and I'm sorry he hurt you and your son like that. On his birthday? Oh my...