Ace? Is that asexual? Alpha? Something else?
Assuming it means asexual, you are in a tough situation since your partner does not want sex rarely or at all and you have a high sex drive. Asexual/sexual relationships can work but you two are fundamentally mismatched. Love is not enough without basic compatibility. He can offer you more sex even though it is not his favorite activity if he wants monogamy. I personally think it is very difficult to maintain monogamy in a 'mixed' relationship like yours. An open relationship is an option recognizing he can't meet your sexual needs.
Is he in counseling to deal with the myriad issues that can come up with being trans? I don't mean to imply he is weak - transfolk are incredibly strong and courageous. But it is a difficult road that may involve some serious issues about his body. I ask because do you realize there is no way you can reassure him out of deep seated fears? They are possibly internal problems that your reassurance cannot touch or ease.
I am also concerned about his desire to control you to manage his fears. That never works. He was that fearful about just going to a gay bar? That is not a good sign. You cannot fix his fears by agreeing to be controlled or by reassuring him. The reality is that you can leave anytime. He needs to face these fears, find their roots and pull them out. This is not your problem. You can support and encourage him but you cannot fix this. Is he controlling in other ways? If he is, and refuses to get help, I encourage you to leave.