Sex once per year in 20s

My(28M) girlfriend (25F) and I have been together for 3 years and initially the sex was infrequent but okay, we had sex about 5-6 times in the first year, which I attributed to us being long distance. The second year we only had sex once a year and she said it was because she was living in student accommodation and felt uncomfortable having sex where her roommates could hear, in addition she got the coil fitted last year and said sex is basically off the table for a minimum of 6 months because of uterus pain and I completely empathise and was being understanding. Unfortunately, only now in recent months is that starting to improve and feel better and she is getting less pain and this year we have had sex once in the last 3 months. In addition to this she also complains of painful sex and I appreciate that this could affect why she doesn’t want to have sex. I’ve advised she speak to her doctor but she doesn’t want to regarding this issue of painful sex.

I am really struggling as a guy because I have a normal libido and usually masturbate 3-4x per week and I don’t feel satisfied sexually. I have communicated this to her several times and she states she will make more of an effort to have more sex but every time we feel like it, there is always something that comes up that affects her ability to have sex e.g. low mood from depression, uterine pain because of her period or coil causing her issues.

In addition I feel like because of her job her work/life balance isn’t conducive to a healthy and balance life (let alone a sex life.) She works a very stressful job working long hours and nights typically doing 48-60 hour weeks and as a consequence she has gained weight significantly over the last 2 years, She has always been overweight since I first met her but over the last 3 years she has steadily increased in weight and I feel this is making it hard for her libido and overall health/mental health and overall self esteem. She does suffer with depression and PCOS and I appreciate that both of these things can affect weight loss and her libido and I empathise with her and do keep encouraging her to get good protein intake and exercise regularly which she has been making a conscious effort to do.

We have sat down and discussed these issues several times but I feel like although we try our best to work through them, nothing hasn’t improved much. I feel guilty because I know it is wrong of me to expect my sexual needs to be met if she is struggling with her stress/mental health and overall work/life balance but I am unsure of what I should do to improve our situation. I feel as if 3 years is now a long time, we are young and I expect sex to reduce slightly as the relationship continues, but I feel we have the sex life of a couple in their 50s/60s which makes me feel unfulfilled and not satisfied in the relationship.

tldr : 3 year relationship with GF, sex less than <10 occasions in total, GF has stressful job, depression/poor mental health, nothing has improved. What else can I do to help support her and improve our sex life.