Dude, Don't panic at all.Thats is universal in a realtionship.The only difference is some ppl step forward to unwrap it while others just let it go and remain in a state of turmoil some time even resulting in the end of realtionship.I am strictly against the idea of "Be A Man".You don't need to a man before ur wife.She already knows u r a man thats why she goes to bed with u.I would recommend u to work more on gaining her trust and persuading her.Have u ever gave a thought why she is against ur idea of buying guitar??Doesn't she want u to look happy and be happy??Of course she does.Actaully,we just hear from ur perspective and u might have some stuffs which u r vulnerable to and u dont realize wat u r doin.In ur case it might be music.What I mean vulnerable here is:  you might be spending a lot of time with guitar and more concerned of different maorrs and tabs than ur househols stuffs which ur wife might not appreciate.U know wat i mean?? Relationships flourishes on the mutual trust and understanding .Let her know wats on ur mind.

There might be some stuffs which she never thought about it or never knew about it so try to explain the stuffs .Last but not the least,if u wanna stay in a healthy relationship ,u gotta increase the conversation with ur spouse.This is one of the common problem for all Nepali ppl.We dont really discuss about anything but just say it and want everything to happen that way.I have seen this with in my family,ppl my vicinity and  relatives.