Are orgasms and successful sex essential for a relationship?

I started dating a foreign girl in a foreign country who's also a foreigner in this foreign country. American guy + Chinese girl living in Russia.
We really fit each other emotionally. As in, we're happy together, we're both affectionate and try to take care of each other.

Unfortunately our sex life has been rather sad. I found that she's sensitive and can have orgasms very easily. I, on the other hand, was introduced to porn at a young age (About 13) Sometimes in WV fathers will give their sons porn in hope that they won't become gay. In my case it was my cousin's father. By the time I was 18 I was looking at hardcore porn. I have been through it all. I just considered the different types of porn as different flavors of life. I went through a 5 year depression after breaking up with my first girlfriend at age 17 with whom everything was much better sexually. I don't miss her and I'm not attached at all, but I remember her simply to prove to myself that I was normal at some point in my life sexually.

Back to the present: I'm 24 and my foreign gf is 20. She enjoys everything we do sexually and always gets off. I can't always maintain an errection for penetrative sex, so sometimes I go down on her or use my hand to get her off. Most of the time we can have sex, but I just never get pleasure from it - It's more like a job. She used to try to get me off, but gave up on that about a year ago. Every time she tries to get me off orally or with her hand - it ends with her sweaty and with an aching arm (and me without an orgasm). She's managed to go for any entire hour before and the entire time I'm trying my hardest and sweating humping myself against her hand.

I've went through different phases (We've been together for 2 years). At first I got rid of porn for about 6 months and stopped masturbating every week. Eventually I would get an aching sack, that I assume most people call blue balls, except mine were red, not blue. I managed to endure it many times.
Eventually I gave up on quitting, giving myself the excuse that I can't just quit masturbating without replacing it with something else.
My fetishes grew. I was never into it before, but I grew an interest in cuckolding, chastity, and humiliation fetishes. I tease myself about my situation and girlfriend, and get some great orgasms from it.
I've been very careful the past couple of months to not squeeze myself too hard when masturbating, so I can orgasm easier now.
It took several months to talk my girlfriend into it, but she let me buy a chastity belt. However, she refused to participate, look at it, or even acknowledge it even existed. I got some great orgasms from it and really enjoyed it after I got through the intial pain of it. Then I threw it away, because it gave me the feeling that I was becoming even more separated from my girlfriend.

It hasn't helped my situation with my girlfriend at all. I occasionally share my feelings with my girlfriend and tell her everything that I wrote here, but she's either too disgusted or too helpless to do anything.

I'm emotionally attached to my girlfriend and letting her go might mean another depression. I tried to write as many details as necessary and I hope someone has the time and desire to read my situation to the end. I appreciate your time. Thanks