Nice gay men often have clingy females who believe they can help the gay men change and get on the right path. Has she not got a life? Has she got designs on you?
On the other hand, for all the presure you must feel, it is kind of a big compliment when another "safe" person (i.e., woman) declares their loyalty to you - especially when you feel so rejected by everyone else.
Fact is you're gay - and reading between the lines, accepting of it - but more importantly, you're disfellowshipped. What part of that doesn't this loyal but dense woman not get? I suspect that at least part of the reason this has continued is because you are not a very assertive fellow. Am I right?
As for her emotional dysregulation, here's where I stand: You must be doing something to allow the little temper tantrums to continue. Would any self-respecting person allow themselves to be subjected to such displays? I suspect you are a very, very tolerant and understanding man, huh? There is no excuse for her behavior...nor for you putting up with it.
It smacks of a juvenile outlook in which she has learned over her life that if she "acts out" often enough, she will eventually get her way. Are you deserving of better behavior from her?
Being gay is who you are - it won't change.
I could tell you to develop a spine and stop allowing her to manipulate you - but I suspect she is an important support person in your life - which explains why her juvenile behavior continues. It's great to have loyal friends - but in this case, the high price is corrosive of your self-respect.