So first off I should probably point out that this is the first time I've actually told anyone about my situation and the reason I'm doing it here is because of all the other people who seem to have had a similar experience and it just feels like a relief, as well as easier, to talk about it here.
My OH and I started dating in our mid twenties and sex was frequent and enjoyable, so when we decided to move in together I simply assumed that everything would continue as before. But within several months I realised that not only was he not interested in having sex with me, but on the three occasions that I initiated sex, I was acutely aware that he wasn't enjoying it at all, which made me feel as if I was forcing him as well as making me feel unattractive and undesirable. After that, I decided not to initiate sex and he's never made any attempt to talk about it, if anything, he seems content to ignore it. The thing is I kept telling myself that it would change, but as time went on I realised that that was never going to happen and now years later, because it's lasted for so long I realise that I've blocked it out so well that I have little or no sexual feelings whatsoever. But it doesn't stop me feeling sadness (and shame), when I realise that I'm just as much to blame for not having the courage to confront the issue.