Help

I’m scared I don't know if I can take care of my kids by myself I know they would be better with me there mom is a lazy bitch that only cares about getting laid. I know what it feels not having a mom around when I was young and part of me can't take them from there mother. But if she is doing a lazy job wouldn't they be better with out her, how do I tell my kids if I get custody why mommy cares more about men than she doe's them.