Okay, long story.. I ran into an old friend that had recently left his 2 children's mother who were never married... he started hanging around and we started a relationship. Now the kids momma is making him feel guilty because she found out about me. Now he's went back to live at home because he's afraid he'll lose his kids. I need to know what to tell him about getting joint custody and how he will go about visitation and child support. He wants to live with me but we are unsure how to go about this at this time.

Just curious: Are you and the other woman going to use the kids to get this guy?
See this: Child Visitation 101: Divorce and Splitting Time with Your Kids | DoItYourself.com

No, actually I have never met the kids. He may be playing me altogether. He has been with her for 13 years but they never married. He says she is immature and he has left her a few times before but only for a few days. He moved in with me the end of November and has went back home 3 days ago. He says he loves me and wants me but he's afraid she will take everything and since the kids don't have his last name we need to know how to go about living together (me and him) and still be able for him to spend time with his children. And also, he's paying the house payment they live in and all the bills. He did mention though that they had discussed selling the house and him giving her ALL the money.

theotherwoman writes: "he's paying the house payment they live in and all the bills."
Who owns the house? In other words, in whose name or names is the house titled? (His, hers, or joint) His case is not simple and he needs a competent family/domestic lawyer.

I would advise him to speak to a lawyer about the matter. Honestly, I would be wary if I were you, since he is still living with the ex. Just be careful, especially if you think he may be playing you. I think an attorney can answer a lot of his questions about how he should go about this.

The only thing is I don't know why he would be playing me unless he just wants to stray because I don't have anything... I'm not sure who's name or names the house is in, but I will ask him when I talk to him again. All I know for sure is he says he wants me but she holds those kids over his head to come home. And I know this because I have talked to her and she tells me that it is best for him to be there because he has kids with her. One of our mutual friends told him that since the last names of the kids weren't his that she could take the kids away and he would never see them again and there was nothing he could do about it. I don't think this is true, but it scared him into going home.