My husband left 2 years ago. Our relationship has been OK most of the time. He still came over for sex for almost a year, I finally put a stop to it. He moved out to get himself some help then come back. In Oct I found out he had moved in with a girlfriend of mine in July. My stepson, who is still with me, and her oldest son were best friends. My kids knew about this and were told not to tell me. He finally moved out the weekend before Thanksgiving we had been talking OK. He was supposed to spend some time by himself and get his head straight. Since he moved out I admit we had sex and it felt great like old times. But I recently found out he had spent the weekend before last with her again and lied to me about it. During major snowstorm that rolled thru last night I called to make sure he was doing OK, he lives in a old house in the country with no vehicle and his power had went out, I was concerned. I still love him but I don't know why. Earlier in the day he had stated that he had everything he should need, but when I called I found out he was back out at her place. The two years he has been gone he has payed me very little money for the two kids of his. I have taken a second job to try to get the bills caught up. When he left he left me with major bills several in my name that I got to cover his mistakes. I filed for divorce in Oct. I am ready for the date but scared at the same time. I have spent 14 years fighting for this marriage. He has threatened me over and over again about taking my stepson away. I have raised him since he was 1 month old. He never knew his mother. When I filed for divorce he had threatened to take both kids. I know he can't get out daughter but my stepson is a different story. I am so afraid that after the divorce he will use the kids, hurt them (emotionally), and I won't be able to do anything about it. Since Thanksgiving he has spent part of 2 days with his son and 1 with his daughter without me. When he was living with her before he spent no time with them and barely ever spoke to them. I can't stand to see them hurt anymore then they already are. I get sick to my stomach everytime I think of the kids going out to her house. I have witnessed her hitting her kids, kicking her kids, and constantly cursing at them. I don't want my kids to witness that, my daughter is getting to the age that she can be influenced by a grown woman. They are both alcoholics and don't put their kids first. It hurts to know that with all the help and support I gave him he would still rather be with her. My daughter don't like her at all and my son only likes her as a friends mother. I'm not sure what I am supposed to do or feel. How can he lie and jump back and forth with so little regard for his kids or me? I try not to think of them together but it is hard. I'm the one that has done all the work to keep this together and now he has a whole new family and I am alone. I'm ready for the divorce, I think, I'm just scared of what will come next for me and the kids.

Get a GOOD lawyer. State keeping a "List of Events" sheet. Write down who the kids are with. As for your stepson, he may be his but if he left him in your care you may be able to get custody of him IDK. If he hasn't spent time with him then the courts may rule in your favor for custody. That's why you need a good lawyer. Get online search out every thing you can on the matter. Document the lies, the drinking, the GF's behavior, EVERYTHING...they say that moving in with someone can cost you custody well the same should go for a man(?) Remind the kids of how much you love them, even seek counseling for you and the kids.
You wrote
"I am so afraid that after the divorce he will use the kids, hurt them (emotionally), and I won't be able to do anything about it."
There is something you can do. You are their mother ( blood or not) and as mother's we fight until our last breath for our kids. Do your homework and you will win. Maybe one of the woman here have more info for you on stepchildren. Good luck

A friend of mine has custody of...let me see how to explain it...she was living with a man whose daughter had a baby. The baby was a drug baby with special needs. The Grandpa and my friend were caring for this child. He moved out (OK, so she kicked him out)and she has custody of the little girl. She had cared for the child since she was a baby and was able to prove she were the most fit parent. DOCUMENT, DOCUMENT, DOCUMENT. Lisa had good ideas as well, and she's right-fight to the end. Hang in there. Prayers and hugs.

i really know how you feel . i been having sex with my ex to because i don't have any friends and no family support ...even though my ex will treat me badly emotionally afterwards. all that we can do at this time is try to be strong and break this bad pattern and get our self esteem back so we no longer allow ourselves to be used. As for the other woman it sounds like your ex and her deserve each other , you deserve better but i know how much it hurts.
If that woman is abusing her children maybe you should talk to a lawyer to see if what you can do to keep the children from that sitution for thier best interest.