Had my girlfriend try cucking me during sex [first time]

So I’ve had a thing for cucking especially with her for a while and I’ve been trying to get her into it. I was really close to get someone involved but then she told me she actually “wouldn’t” be interested in going through with it. Well the last times we had sex, I would stretch her pussy out really loose with my hand trying to fist her and get pretty close to fitting it all in. I would get her really loose and then insert one finger and ask if she could feel it to which she said “not really”. I would then put my cock in and feel how loose it was. I decided to ask her if she felt it, she said no. I told her to keep going with the humiliation and she said how small I was, how i wasn’t even that deep and not hitting her cervix. I asked her about the gangbangs and cucking she previously told me no about and she said she’ll fuck so many cocks and real men. She got into it and said she’d make me watch and how their cocks would be so much bigger than mine and how she’d let them fuck her ass too. I thought this was really hot because she never lets me do anal anymore so it means she’d let them do something she wouldn’t let me do. For some reason, during this kinda sex where she humiliated me like that, my dick had trouble staying hard like usual which just added to it because my cock can’t even get hard enough to fuck her. I ended up finishing inside of her and I felt a surge of intense regret and shame that I don’t usually have from sex with her. I asked if she meant any of that and she said of course not she was just “going along with it”. I did have to kinda talk her into it and tell her what to say at first and I feel like it wasn’t completely sincere but at the same time I believe she’d definitely fuck someone else if I gave her the chance. I also feel like my cock wasn’t big enough, especially with how loose she was at the time, I didn’t hit her cervix and I definitely felt like it wasn’t filling her pussy all the way. It hurts but I feel like she’d love to take a big cock that can fill her completely. I remember using a big dildo on her and she was squirming like crazy with it, a far cry from what I can do to her. She’s also 5’4” and 130lbs (more muscular) and I’m only 5’8” 120lbs and she wants to be thrown around by a real man and dominated which I just can’t do all the time for her. I’m also 6.7” which isn’t “small” but it still isn’t huge either. She loves me and tries to please me the best she can but I can tell she wants more in her sex life than what I can provide.