It's Time for This Mama's Boy to Man Up
Ask Demetria: If his mother starts taking top priority, you have to demand that he set better boundaries.
By the nature of the relationship you describe, I'm going to guess that his father isn't in the picture, Mama doesn't have a man-friend and your man is either her only child or only son or the oldest. And I make that guess because the relationship you describe between your man and his mom sounds more like the relationship of a couple, not a mother and son.
Without a father around, they've probably had to rely on each other a lot over the years, and somewhere in that time, they blurred the lines of their proper roles. Unfortunately, you can't redraw those lines for them. At least one of them has to recognize that it's a problem and begin setting more appropriate rules.
His mother inviting the ex to the family event crossed even the furthest of lines. If your man hasn't recognized that, conserve what will be your wasted breath on trying to get him to see the problem and end the relationship.
Assuming he does recognize that Mom has gone too far, stop complaining and lay out what boundaries you need him to create with his mother if he wants to continue a relationship with you. So we're clear: She should not discuss his ex in front of you, he should not tell her about your disagreements and she should respect you at all times, even if she doesn't ever come around to liking you.
The errands or trips where she needs a driver -- unless it's an emergency -- should get a designated day and time to be completed, not whenever she feels like they need to be done, which seems to be whenever he is with you.
Their pattern has been in place for a long time -- way before you -- so he may not even know where to begin solving these issues with his mom. The onus is on him to speak to her about what needs to change, but the two of you should come up with creative ways for how he should address her. Whatever you come up with, when he speaks to her it should be, "What I want is ... ", not "G.V. thinks ... " That won't solve anything.
Finally, the conversation about whether you should move in should be tabled until you see positive change over a period of time. It doesn't make sense to move this relationship to a higher level when the foundation is so out of place. If you don't see any change between your boyfriend and his mother, remember, you always have the option to change boyfriends.
Demetria L. Lucas is a contributing editor to The Root, a life coach and the author of A Belle in Brooklyn: The Go-to Girl for Advice on Living Your Best Single Life. She answers your dating and relationship questions on The Root each week. Feel free to ask anything at firstname.lastname@example.org.