First off a big hug for being brave enough to open up about this. What you have written is not uncommon at all, so you are not abnormal in any way. Gender and sexual orientation are two different things and it can be hard to untangle them at times, especially if you are still sorting your gender issues out.
I went through the same thing when I was doing anything sexual with a woman, and have finally concluded that as well as being a woman I am a lesbian. Actually lesbian with pansexual possibilities is probably a better description.
By digging into my past I can see that this goes back to an age before I was even aware of gender or sex as concepts. Lots of lesbians have written about how they felt the first time they noticed another girl, at about 8 years of age or even younger. They had no idea about sex, but just felt fantastic. If you do end up on HRT you will find you male sex drive quickly disappears, and is replaced with a woman's. They are very different.
As for not being able to go back, that really only applies to SRS, anything else is negotiable to a greater or lesser extent. There are lots of exits on the Transgender Highway. Main thing is, nothing is going to happen in a hurry, and it is worth taking your time.
Karen.