I don't understand my girlfriends signals

We've been together for almost 2 years and everything is really great, we hangout a lot, we trust and enjoy each other and flirt an so on, but I don't remember the last time we kissed kissed. I let her initiate intimate interactions because I got tired of being rejected or feeling like she was only doing it because she felt like she had to. We used to have sex once a month at the beginning of the relationship, not so great because she didn't like to touch me as much as I would like to, I brought the topic and she would tell me that she is sorry, would try to do a better job, comunicate, etc., but at the end things just didn't change, but at least I felt desired. But now we've been month's without even kissing, and she asks me for intimate photos or teases me about sexual things without things going anywhere and I feel confused. How can I address the topic?? I feel really sad about everything and it makes me feel like a terrible person to consider leaving the relationship because of the lack of "it" happening.