Sounds like you are stuck in a rock and a hard place - not fun :-(

Do you ever consider therapy together? It can work for some people. I guess there are a few options, ie -therapy, calling it a day or explaining how she is making you feel. Its unfair to feel intimidated in a relationship, and its also unfair to magically know what makes someone happy. You're not a mind reader. People change, people grow, relationships change, and things that might of made her happy then, might not make her happy now. She really should explain some stuff to you - a breakdown in communication is never good. I do wish you all the very best, and I hope you guys manage to work it out - you sound fab, warm and kind to worry, I hope she see's it too.