What can I do to make my girlfriend want me again?

We has sex 1-2 times per month, Its very frustrating. We have been together for 5 years in june, shes had ovarian cancer 3 times, multiple surgerys, histerectomy.. shes 23 as of feb im 22 in march. idk what to do anymore I run often workout almost everyday I'm in good physical condition and have supported her through alot but the last round of chemo I almost left and left her alone in the hospital for awhile. Her family was there it wasnt like she was alone, there was someone there everyday and night it just wasnt me as much as the times before and I feel she resents me for not being there for thinking about leaving, and it seems as though she is trying to distance herself from me and the relationship. Every little thing I say pisses her off and we constantly argue... she has extream hormonal imbalances and canot take supplement cause her cancer feeds on it.... Any advice as to what to do would be helpful. Sometimes I feel like maybe im just being selfish but I am just so frustrated

Something you might want to think about is if you guys were doing well or not before she found out she has cancer. If you guys weren't then you're just going to have to admit to yourself that your relationship isn't going to work. If it did then you should talk to her about how to come up with a solution to the problems in your relationship. I don't know if this is selfish or not because I've never been in your position but you guys should talk about what she might forget to do for you because all the focus is on her and cancer. It seems like you're sexually frustrated and from my little knowledge, I don't think that's someone who's going through chemo's thinks about. Even though it's difficult, I think if you love her enough then you both can compromise on something. Hope this helps!