Is it possible you aren't ready to commit to anything serious yourself yet? You measured the time since you've been single in months, which is sort of interesting to me because it implies you are still struggling with the end of that relationship. And if you are, hey, that would be ok. It's a pretty huge adjustment. I don't know the circumstances that led to that, but maybe it had an impact on your ability to trust men for now? Is the child's father still in the child's life?
Right now you are choosing casual with sex. If you own it, really own it, it will take you further in having your sense of control versus feeling like this is a result of "how men are". There are men who prey on women they see as vulnerable, but that's not limited to single moms. And there are plenty of good men who build lives with women who already have children.