Have you communicated your feeling outside of a fight? Everyone is typically heightened with emotions during fights and may not be as receptive to communicating. Maybe a sit down discussion to ask her what you can do to help with your intimacy might help. If she is feeling self conscious or unattractive you could try giving her more attention or positive comments during your normal day to day interactions. If she feels your comments are sincere and not just to get sex it could help with her own self image, although that is not something you can control. Sometimes your partner needs more intimacy during the day to feel connected during sex. Us she able to talk with you freely, do you engage in her thoughts and feelings normally? I would recommend finding a hobby or activity that you can do together, and one for her that she can do on her own.