Hershey's Kiss,
I have no words of wisdom, just wanted to send you a hug. Nothing is simple when it comes to matters of the heart. All I can say is make yourself and your kids your first priority in whatever you do.
I have a son by my AH, he's 2 now, and has only really "known" his father for the last 8 months, after he entered himself into rehab. Before that... well, lets just say he wasn't around.
I have a lot of "woulda, shoulda, coulda's" in my head, because I knew of my AH problems before committing myself to him by marriage. He had been clean for a year when I agreed to marry him, and then relapsed 3 mos after we were married, right after I found out I was pregnant with my boy. It was a nightmare ride after that, until I finally seperated myself from him.
I wish you luck with a difficult situation. The people on this site helped me when I thought no one could understand how much I loved this man, even after the aweful things his addiction did to our relationship.
I agree with mooselips, educate yourself before you go further. Knowledge is power after all. Hugs to you.