The title is basically the entire point.

My LTR has a super high sex drive. She's down to have basically non-stop sex every time we see each other.

This was fun at first but it's honestly getting annoying. I'd probably prefer to have sex about 5 times a week, and sometimes just a quickie. Not a marathon sex session.

I have had my hormone levels checked, they are all normal. My health is fine.

I realize this is a "good problem" to have (and I'd rather deal with this than a sexless relationship) but it's a problem nonetheless. When I can tell she wants sex, I feel like I'm being a bad leader if I don't initiate or reciprocate her advances. I feel like my role is to be hornier than she is.

How can I get the fuck over my feelings about this? And how can I reject her properly?

I get freaked out thinking that if I reject her too often she'll want to get it elsewhere.