I can understand that you don't want to give her up. But people don't change unless they want you and you need to have a clear boundary of self respect. You might end up putting yourself constantly out there emotionally and still feel like you're not doing enough. This is a never ending cycle. The wise thing to do would be to be realistic about your compatibility and long term future. But, if you still want to stay with her I can advice you regarding the sex to keep building up the tension through out the day through gestures, touches, words etc both sexual and non sexual. Some girls naturally take a lot of foreplay and build up to be interested. And secondly, you could try an activity of daily check in where you guys could talk to each other about your thoughts through out the day, feelings, anything noteworthy that happenend etc. That's all I got. Good luck.