My husband (38m) won’t touch me (36f). Sexless marriage.

We've been together for almost 10 years in total, and have been married for 4 years.

This problem started around 2 years ago. He won't touch me, and when he does, he doesn't perform. In the few times he does perform without help, he finishes within minutes. In any case, it always feels like it is a chore for him. I feel no passion from him, no desire, nothing.

At first he said it was work stress related. Things changed for him at work (for the better), but it continued to decline in the bedroom. I've always had a higher drive than him, but we found a good balance and I was happy with that.

We've talked about it, I was always honest. Told him I need us to work this out, that I need sex. He will make an effort if I ask, which to me totally defeats the purpose. He went to the doctor, levels are fine. He says he loves me but his body doesn't respond.

I have been nothing but supportive all this time, not making a big fuss when he "fails", willing to try again. Doctor gave him Viagra months ago, he only took it once.

It is getting to a point it is taking a toll on me mentally and physically. I am frustrated, I feel unappreciated and unwanted. Self steem is on the floor. It is getting hot, but I haven't cheated. I suggested to open the marriage, to which he almost agreed but changed his mind last minute, asking me to keep trying.

How long is too long to keep trying? Any thoughts?

EDIT: just to clarify, I'm not the type to not be in the mood sometimes. I'm ALWAYS in the mood, like always. I can't remember ever saying no to him in 10 years.

EDIT2: him: extremely healthy and athletic, goes to the gym every single day, so not a lack of exercise or bad diet. me: tennis player. We're on holiday at the moment. I get constant looks by the pool, by the tennis courts, on the street. It's not a looks problem either.

EDIT3: I recognise that my advances could potentially be a turn off factor for him, so I stopped. I gave him time and space. I did not touch him sexually or acted flirty for a while. I waited for him to come for me. That went on for months, and we didn't have any sex AT ALL as a result.