Should I be upset that my boyfriend let his baby mama approach and hang out with us in the club?
That's quite a predicament. Why do you think that she's his baby mama? Has he known her for a long time?
She's my boyfriend's ex. And I'm pretty sure he's known her for almost two years
It's okay if you do not want your boyfriend's exes to intrude on your time together. However, you should not try to stop your boyfriend from seeing the mother of his child, as this is still someone important in his life.
I know but I'm still mad.
It's natural to be mad and jealous because the kid is going to tie your boyfriend to his ex forever. It's something that requires a lot of trust in the relationship, but I see how much he loves you, so don't worry about him. Plus, if you put yourself in his shoes, he probably had no choice.