You're a rebound. Sorry. It has nothing to do with what treatment he's giving you.
The only reason he has hit her up a few times, though he hasn’t done it in like two weeks, was for sex.
That's nothing to gloat about. The way this reads, up until 14 days ago (out of your 7 months), he's cheating on her with you and on you with her; he's been stringing both of you along and you're convinced that because of a couple of trinkets and you mom's interference, he's more serious about you than her. If he was done with her, none of this would be going on.
Tell you what: get both of them in the same room and put your questions to the both of them and watch who lies the most. Right now, your boyfriend is sus a. f.
A word of advice: don't let your mother manipulate you into something when you're not paying attention to the signs he's giving you that he's not the one for you. Quit calling him her "son in law". He isn't until the state weighs in with a license.
People treat you the way they feel about you
If you choose to remain with someone who doesn't treat you well, you cease being the victim and become the volunteer.
~Derrick Jaxn -- look him up