My girlfriend who i am engage too always bitches at me cus i smoke weed?

When i am high i treat her good as gold, i treat her no different, it do not make sense to me, cu's it do not effect her really, if i treat her the same wheres the problem, no she do not smoke it, she hates it, ya i know but really still, is there any females out there that can shed some light on this please? and try to relate on her behalf? please i want to fix this thx.