My advice is to try to make her feel appreciated and loved. Maybe that can be down with cuddling or small gifts. From what you described it sounds like she is feeling like she is being ignored. I added a lot of stress into my relationship by focusing on school and work and not on my wife. Try to keep things exciting and alive. Bring her flowers. Go out on dates and places she likes. Sometimes by touching my wife I can excite her. I don't mean grabbing her vagina. I stand behind my wife and start kissing her should moving up to her neck, then I whisper into her ear. She enjoys that. She doesn't like when I say lets go have sex. It makes her feel used. That is my take on it. You know her better than anyone. It sounds like she just wants you to pay more attention to her.