I am not sure about being attractive, I think I was okay before. I did not date really for almost 3 decades so I may not be the best person to give advice. I can only give my own experiences.
😊 I always thought that I would be promiscuous after transition, it never happened. Not from lack of interest from men though. Seems that I lack something required to be a hussy, who knew. I do get a lot of attention from men however. I don't know why they would be interested in me but they are. I don't know, maybe straight men are less discerning than gay men.
I can't give reassurances about your bf, sorry, I can say say that to be afraid of NOT being attractive as early as you are in the process is silly. You are borrowing trouble. BUT! I understand, I do. I am not a gambler at all, why give up what you have in the hopes of getting something more? Sweetie, it's not giving up anything, it is just giving up the known for the unknown. Transition is a leap of, not faith, but hope.
I think it is Mark 8 um... 36? What shall it profit a man to gain the whole world but lose his soul? I don't know, it's been a while and then some. It's about being happy, what will make you happy babes? Head in that direction and all will be well.
Really, I would not worry about men though. I may never be hot but men don't seem to care one bit. Not even being trans is a deterrent to them from what I have experienced. So head up, shoulders back and go get em honey. 🙂