OP you sound like you have a mature approach to this but I wonder if a male perspective might help here a little.
I got married at 22 (now 47) to the first woman I had ever been with. Sex was always sporadic even just after marriage and before children, and I always found it very frustrating. From my viewpoint it always seemed my DW had zero interest. On the rare occasions we talked it was a fairly ?standard? conversation that many others would have had ? she said I should make more effort to be romantic and get her interested, I thought that she never seemed interested even if I did try. As time went on I just couldn?t be bothered to try any more, and when I suggested talking about the kind of things she might enjoy to make it better she refused to talk at all.
I believe it is major contributing factor to the fact we separated 10 months ago after 25 years. From that many other issues built up and eventually caused her to leave.
But what amazed me was that about a month after she left she said she never felt ?desired?. I found that really hard to understand, but assume that I never really approached it the right way. But I suspect she thought I had no interest when that couldn?t have been further from the truth.
I have met someone else who is only too happy to talk about anything in our sex life and it makes things so much better.
The main point from all of this (forgive me for unloading) is that communication is absolutely critical. It was really difficult for me and exDW to communicate over this and I am convinced that had we been able to talk like adults (starting at 22 and even up to this age) and met somewhere in the middle, we might have still been (reasonably happily) married.
The thing to remember is that there is nothing to lose by talking reasonably and everything to gain. And nothing will change of its own accord, unless external factors are having an effect. And your DP needs to know that.
I agree that you should reconsider your relationship if you are willing to try to work it out with him and he is not, and also if you do talk and it turns out you are not compatible then you should end it, and not ?hope for the best? because that won?t happen, IME.