Hey, Mom, think of all the AMAZING men that were raised by single moms. This is fact too.
I'm in your boat, divorcing, and my son is 5. It breaks my heart that his dad is a bad person, but he is. I haven't succeeded yet in successfully raising him alone, but here are the things I will do:
1) Continue to be the happy, confident woman in charge who doesn't bemoan the fact that I am alone and doesn't say bad things about the no good dad.
2) Teach my son manners and respect for women, morals, and raise him reading about and watching good role models while he's young, not bad ones.
3) Keep him around nice men. I have him enrolled in a great community of men who have taken him under their wing in Tae Kwon Do, he's starting boyscouts when able, we have a really nice neighbor who lets him help wit yard stuff, we have nice Mennonite friends and the farmer lets him help on farm, I just met a nice cop through a friend who is going to give him a tour of police station....I have friends willing to hang around him play catch and stuff and always make him feel welcome. I'm actually forcing myself to be much more social than my nature just to get a good community built around him.
4) And conduct yourself with DIGNITY. Do not glom onto any boyfriend any time soon. And when you do meet a GOOD SOLID MAN who would be a great influence and dependable father figure, EVENTUALLY you can introduce your son, but don't let him see you dating around and "needing" the attention of men you barely know. This will not give him a good representation of how men and women should interact.
Let's wish ourselves luck but we KNOW it can be done and has been done many times before.