I can see how much you are hurting and upset by what is going on in your life.
I am wondering if *part* of the trouble can be linked back to the hormonal treatment you are following.
I don't pretend to be a hormonal expert, but often there are links between problems women have with desire after surgery and what is going on with their HRT.
If you are having itching and burning after sexual activity, then maybe you have some vaginal dryness that could be dealt with --- and you say you have no desire--- that could indicate a need for a little bit of testosterone...
I don't mean in any way whatsoever to discount your emotional unhappiness - but I think that one problem might well be feeding the other in a nasty circle that you can't get out of.
At least if you get your hormones checked out you can get an idea of where you are and maybe make some changes that will in turn help your mood improve.
I know what you mean about weight gain making you feel unattractive - in the years before my hyst I went from about 145 up to 195 !!!! and I am convinced that a lot of my problems were due to hormonal imbalances (in my case thyroid to start with and then others).... But one thing I know is that our hubbies often don't seem to mind too much when we put on weight - we are the ones who feel rotten about it.....
I hope that you can soon find the right path to lead you back to the relationship you want to have.