I tried, and eventually failed at avoiding transitioning for every reason under the sun until I was 32. Two marriages, cancer, kids, etc. etc. There was a point where I couldn't hide it anymore, dysphoria got worse and worse as the years went on. I know a lot of people that have similar stories to me, all of us are way happier after having transitioned even though it has meant that life has changed.

If you can make it work, then that is great. If you can't then you aren't alone, and you aren't a bad person for giving it a try. You aren't being honest with him though, he thinks he is in a relationship with a guy but isn't... He is in love with someone that isn't 100% real. Those little lies are the things that build up and haunt you if you do get to a point where you have to come out.