By your description, it doesn’t sound like it’s a good match for a marriage. Mainly because he doesn’t sound mature enough to tell you what his true issues are with horse ownership, showing, etc. Rather than delve into what his true issue is, he takes digs at you and what he knows you are passionate about.
I’m sure there are some people who have given up their time with horses, I’m not sure they would be on this BB.
You have to go with the Dear Abbey frame of mind: Are you better off with him or without him? Does he add enough to your life to make the absence of your passion OK? Only you can answer that question.