My [23f]boyfriend [28M]keeps inviting me out with him and when the day comes he like he never did. How do I confront this?

I pre apologize for the long winded explanation. (I’m a context queen)
So me and my boyfriend K have been in a relationship for almost four years now. When we first started dating it was very textbook lovey dovey, going out fairly frequently even if it’s just to walk in a park,play basketball etc. but after he moved in it’s like the charade was up and he stopped wanting to go out, progressively began playing video games more and going out less. My overthinking brain believes it’s because I’ve started gaining weight and he’s embarrassed to have me around his family or in public. In the 3yrs and 8months we’ve been together I’ve met his parents 3times for less than 5 minutes per interaction. In the beginning of our relationship we would spend most holidays apart due to my family being far away. That was fine for us until around year two he began inviting me to spend these holidays with him and his family, I’d agree and when the day would come he’d be looking nervous and would casually say that he’ll be back from the family function at whatever time and to enjoy my day. After the first two times of this happening it was almost comical how he would just make up my mind for me that I’m not going. For example his previous birthday him and his friends planned a trip to the beach, he invited me weeks in advance, I was so excited to finally meet his friends and spend the day with him. When the day came he was up bright and early hours before he told me we would be leaving, dressed for the beach and gave me a kiss on the forehead and said to enjoy my day. I was SO blown away that I truly even now don’t know how to react.
I tried to bring it up but anytime I address something that bothers me he IMMEDIATELY goes into a “I’m sorry I’ll do better” speech but nothing ever changes. Literally everything else in our relationship is fine aside from this one weird behavior. How do I even address this and effectively explain how hurt and abandoned I feel when he does this without him wiggling his way out of answering the question by saying he’s sorry.
Ps. It was his bday yesterday and he invited me to dinner with his family today but rushed out of the house telling me to enjoy my day same as always and it just made me want to throw up, how casually he dis-invites me to things he was never forced to invite me to in the first place.