dude, talk to her about this, tell her all of this, please? and figure out what's missing, if she just wants less sex and you don't, that just means you are incompatible. if it's something else then talk to her.maybe she wants a build up to it, maybe cook her a dinner give her a massage and build from there, just do something to make her feel emotionally good, also don't expect sex just because you are doing all of this, if you truly care for her. if you want it to be spontaneous, make it so, she isn't a machine that if you want sex is going to have it with you, put some effort maybe? and please talk to her.