We been separated since feb/09 but was leaving not as a married couple for about 2 years before that just staying together for the kids... ok so he left,got into trouble with the law,now he's in jail,but can get out early like September,if he has a place to go and some to look out for him... and yes you guessed it ,he wants me to take him back ,but I do not want to ,as I have fallen in love with someone else and I want a divorce ,but now my son is mad at me ,he's 10 because he wants his dad home... so any help from anyone out there ,please...

He made his bed and now he is looking for any easy out AT YOUR expense. Don't do it.
Helping him is understandable but not @ your expense.
Kids see things from their own limited understanding so he is going to be hurt and angry but if your reasons for not being with your husband any more are solid enough he is just going to have to accept it.
Reassure him that he is still his daddy no matter what and he will have plenty of time with him when he gets out but you have adult problems that make things have to be the way they are.

I think, in My opinion, that you should do what makes you happy. Your ex is in jail and must not be a good influence on your son. He will get over it as most kids do. Explain to him that even though his father can still be in his life, he's not going to be in your house. GOD bless you at this difficult time.

Thank-you both for you help,ver much apreciated...