I met my current boyfriend just after I split up with my ex and knew he was keen for a while but I was not ready to see anyone new. However, after a while I agreed to go out with him and have been seeing him now for a year and five months. During the first four months we had regular sex (about 5-6 times a week). Our living arrangements then changes as I moved back into my parents about 9 months ago but about 6 months ago our sex life deteriorated rapidly. We see each other every day and go on holiday together but he never wants to have sex. We can go at least a month before sex becomes possible. He ALWAYS initiates it but when I respond he backs downs, fakes a headache or tiredness or causes an argument. Outside of the bedoom our relationship is great, he takes me on trips, compliments me and buys me gifts and is interested in my life but as soon as we are alone he loses his nerve. I have even tried to tempt him with underwear and sexual toy, which he always agrees to but never wants to act out. I am worried about whether the issue is physical or pschological and whether it is to do with me or him.