Hmmm, Love has a lot of give and take... but it should be fairly mutual. Asking her about her needs and talking about your needs does not make you an asshole, Forcing her into having sex with you would make you an asshole
(Not physically forcing her as that is rape, It's Wrong and makes you an even bigger asshole :P)
When you talked to her was her only reason that she does not have physical needs? I personally dont know if there is a whole lot more that you can do other then talk to her, assuming that you two still go out on dates... May seem like nothing, but having fun and new experiences will help a relationship that's in a repetitive rut.
No need to just quit after 3 years, but the thought is understandable. If trying to change the daily routines doesnt help then ask her what she thinks could help as you two, Dont try to fix everything yourself as it wont always work. If neither of you know what to do or what you want then it may be an option to take a break
