I have this problem too and I think people don't discuss enough how much it could be biological. I think solving this could be a next frontier in chemistry (now that Viagra et al took care of the impotency thing, which everyone interestingly also used to say was purely psychological).

It wouldn't surprise me if you have non-sensitive penile nerves combined with low serum testosterone. You need a motivated physician who is sympathetic and doesn't just shove you off to psychotherapy (which didn't work for me, sorry Mr. Counselor).