Let's step back a second. Lots and lots of trans women develop and have long term monogamous relationships with no thought of being sexually active with others.
However, there used to be common discussion of what was called the "slut phase" in transition (forgive me, but that's not a name I created). Older documents on the web sometimes talk about this.
The problem is this - you're hormonally and emotionally very like a teenage girl, but you're an adult and have no mother and father to reign you in, so you are tempted to give in to every wild desire you ever had.
Lots of us (not all but lots) experience this, but we also have to get a grip on ourselves. We need to mature, we need to respect ourselves as women, and we need to be more comfortable with our identities and not feel the need to "prove" anything sexually.
I actually spent some time working through this. I never mentioned it directly to my therapist but I think she sensed some of what I was driving at and she continued to focus me towards respecting myself, learning to be comfortable as myself, and figuring out my true personal needs versus fleeting wants.
You are not weird for feeling this way, but your conclusion, that we can't be honest with our romantic partners isn't true either. Lots of trans women do achieve that. Lots of trans women never experience the drive to be hyperactive sexually.
A question you might ask yourself is whether you are willing to lose him for your own behavior? Finding love is hard enough. If I get that fortunate, unless the guy has real issues, I plan to hang on as best I can.
