Is it okay to break up 5-year relationship over bad sex life?

I (25M) have been together with my (25F) GF for 5 years. We live together and have the stereotypical "everything is perfect except the sex" relationship. She is happy with our relationship and wants to get married but I am just confused about what is happening

The issue is that we never have sex... like ever. Last time we had sex was 1.5 years ago, and before that it was 6 months of nothing. In the first months of the relationship we were both virgins and started having sex 1-2 times per week, but this quickly dwindled. I would try to initiate something and she would tell me stuff like "why can't we just cuddle?" so I stopped and felt pretty embarrassed.

I tried talking to her once 2 years ago but it went very badly. It went exactly like this: "Can I ask you about something?" "Sure" "Is sex something that you enjoy?" But then she started to cry and wouldn't talk to me, and was mad at me the next day. So the conversation didn't get very far. After that I just gave up initiating completely.

I found the courage to bring it up again recently and it went a bit better. She said she thought we would "figure it out naturally eventually" but also said there are certain things she doesn't want to do: not into blowjobs, not comfortable if roommates/neighbors could hear us, not on weekdays when she is tired from work etc. She said she was never abused or anything but she is on the pill so that might have affected things, but at this point I don't think the reason matters, it has become such a negative thing for me

She says she wants us to start having sex again but I am not sure anymore. I don't understand why she never wanted to have sex with me and why she never brought it up or seemed bothered. She doesn't seem to have an answer for me and I just feel bad. AITA if I just leave? I feel like shit.