<human>: Give me the gist of the text in a nutshell

Okay, so about three months ago I started dating Tristan. He's sweet, makes me feel pretty and happy and we get along really great. I like him a lot, and I'm definitely interested in sex with him, but I'm not completely sure I'm romantically interested in him. 

I guess it's a bit more complicated than that. I'm not sure I can be romantically attracted to anybody, as I never really have been. Or maybe I'm just not sure what it feels like? Or if it's important for a relationship to thrive. 

I honestly just love calling him my boyfriend, telling people I'm not single and just sitting with him watching shows like friends and sometimes having sex. I suppose that's a relationship, but I feel like there's something missing in me that just makes it feel 'eh'. When people ask about my relationship I just shrug. I feel like I'm lacking, especially when I see people in the early stages of their relationships gushing over their partners. I've felt like this in every relationship. There's no fluttering heart or blushes or excitement really. 

If I feel this way is it even fair on him? He's clearly very taken with me and all I seem to muster is 'eh, it's okay'. Will I feel more as time passes maybe? I'm all sorts of distressed. Maybe I'm making a mountain out of a molehill.
<bot>: I'm not sure I can be romantically interested in people, and, if I can't, is it fair to date somebody who is?