While not exactly the same, I was married to a straight man for 6 years (together for 8) who I'd met long before realizing I was trans. When I started exploring and eventually came out he was supportive of whatever steps I wanted to take, but ultimately /I/ felt uncomfortable knowing he wouldn't be attracted to me anymore if I transitioned and ended up trying to convince myself that it's not something I wanted. We separated last year (mostly for other reasons) and I started HRT 8 months later after realizing that I'd been holding myself back for other peoples' sake, and I'm much happier for it. I'm sad that things ended with my ex, but happy to know that there are plenty of people out there who are attracted to me for who I am now.

I can't really tell you what to do since it comes down to whether or not you feel like you need more than binding/dressing masculine in order to be happy, but either way it doesn't sound like he takes your feelings seriously (you said he refuses to believe you want to be a man) so it sounds like a good idea to sit him down and have a conversation about it. Maybe talk about your respective needs and expectations.

Best of luck! (And apologies for the wall of text, whoops.)