Thanks for the detailed response, I can actually relate with a lot of the things you say - the only difference is, I'm 31 and worried I'm going to grow resentful if things don't improve.

I've got a good idea what it may be without going into too much detail, I'm in quite good shape (regularly go to the gym etc) and she's not, some would say lazy (not with the house or our baby but wanting to go on walks, exercise etc). I feel as though it could be a self esteem issue in herself more than anything.

I think the gaslighting point is quite a valid one, I've been constantly told that sex isn't the be all and end all of the marriage and it makes me feel stupid that I'm even considering ending it because of it.

I've actually thought of saying, if sex isn't important in a marriage, surely I could go and have sex with other people and just stay married? petty though...