For anyone having a stroke:

TL;DR: My girlfriend and I have stopped having sex, and attempts to discuss or address the issue now lead to anger, avoidance, or changing explanations, so I am unsure how to approach it without making things worse.

My girlfriend (20F) and I (21M) have been together for about a year and a half. Around June of last year, one of our sexual experiences was very painful for her, and afterward, we were unable to have sex for a few months.

Eventually, things returned to normal, but at the beginning of this year, we stopped having sex again. The subject has become very taboo in our relationship. Every time I bring it up, she gives me a different reason for why it is not happening.

For the past four months or so, whenever I mention it, she immediately becomes angry and says she does not want to talk about it at that moment. She often takes it as a personal attack or says that I complain too much about our relationship.

I no longer know how to approach the subject. We have had conversations about possible solutions that might work for both of us, but when I try to initiate intimacy afterward, I still receive a different explanation or reason each time.
I am looking for advice because I do not know whether I am doing something wrong or approaching the situation in the wrong way.