TLDR, Ive been unable to cum during sex, probably because I have to tense my legs up to reach orgasm while masturbating ever since I can remember. The only sex position we've gotten to work is missionary, because every other position we try seems to hurt her. And I have no idea how to tense up my legs during missionary. I've been feeling unsatisfied because I can't cum from vaginal sex, and she has to give me a handjob which is nice but I would much rather masturbate. Ive been trying to masturbate without tensing up my legs to see if I can train myself to, but it just seems impossible and very irritating

So I've been dating my gf for 8 months now, and we've been having sex once a week or so. Neither of us have much experience, and especially my gf, I was her first boy friend and sex partner. Whenever we have sex, we both feel really good at first, but neither of us can seem to reach orgasm. My gf ends up being tired and wants to stop. She usually finishes me with her hand or mouth, her mouth feels really good when she can go all the way, but it doesn't fit and only can do it when I'm soft for the first 10 seconds or so, but that's a different problem.

With her being unable to orgasm, I've been trying to communicate what I can do or anything we can try to also make the experience better for both of us, but she keeps saying it's not important to her. I've told her that it is important to me and we've been trying to improve it for the both of us