Maybe it will help to hear from a trans guy....Seems like trans folk go through this same experience regardless of whether they are FTM or MTF. It is really hard to put into words. I can relate to what you said about ' Am I attracted to this person because it's sexual or because that's who I want to be?" I struggled with that for a while.
When I was young I felt very male and hetero. I feel like the confusion came from the fact that I was not in the correct body. Like I could look at a stereotypical romance narrative in a movie, for example, and simultaneously hate the male lead because he was getting the woman I knew I couldn't have, yet I also thought "Yeah, that's me, I'm hot, aren't I?", and then anxiety because I thought he was hot enough for her to want, which made me wonder if I were feeling some attraction...and really, if you are even slightly bisexual, that could be true, but it doesn't mean that you have to stay in the body you don't want to be in. But our enemies would have us believe that is the case. You give them an inch and they will take a mile.
In that sense, I feel like it is important to keep the sexuality part of it off the table for a bit. Or at least look at it like "Well, would I feel *more* comfortable in all of my attractions if my current body or in a trans body?" Personally, I felt like as a guy I could finally be free to choose whoever I want and not care what society or anyone else thinks about it. But staying in my female persona there was way more anger.