Need advice on what to do with my ex-girlfriend?

Well heres the story, i had been dating my girlfriend for a while and i made a little mistake that made her break up with me, so she went to another guy kyle because she was mad at me. Now about 2 months later it turns out that she is pregnant, but heres the thing, they broke up for a week or so because they were in a fight and we ended up having , so the kid could be mine or his. (She believes it is most likely his because he didnt pull out) Anyway, kyle is a bad guy, hes a pot smoking, lazy kid who gets by with puting in minimal effort, and i dont think he will take care of a kid what so ever. So im wondering should i be there for her and father her child and treat her how she should be treated, or is that just a big mistake and i shouldnt bother with it. I can tell she is afraid of what is going to happen, and i dont want the kid to suffer because his dad is too big of a d-bag to take care of him. I guess thats the only reason i even concider it, because i think that if she stays with kyle, her and that kid are going to end up 10x worse than if i was involved. What should i do?