Painful intercourse

So my boyfriend and I have been tryyyying to have sex for a while but every time we do I have to call it off because I am in so much pain. I originally diagnosed to problem being that you know what I'm a tiny person (5'1, 100 pounds) I must have a tiny vagina he's not a tiny person (6'1", not sure his weight lol but like he's 6'1 so definitely significantly more than 100 pounds) maybe i'm just too little and I need to work on positioning. So we did/do me on top so I could position myself well. Pain was immense. I was waaaaayyyyy under lubricated, so I got lube. We tried with lube, it works to get it in but we still have to go so very slowly and let myself adjust before any sort of movement can happen. And if it comes out I have to reapply lube. And is not like i'm not turned on, I very much am there's eons of foreplay and i'm very attracted to him and he's incredibly kind and understanding and patient so i'm never nervous because I know I can call it off and that he'll happily cuddle the night away instead BUT no matter what I do, this pain never subsides. It's like I have instantly self-repairing hymen. The only thing that's had some minor success was this fancier expensive lube I had a tester of and trying it doggy-style to get a better angle, but even then it was only fine for a short period of time, eventually the lube stopped being sufficient and I felt so much pain.

What the hell is going on? does this happen to anyone else???