Using a throwaway for obvious reasons.

So I learned about TRP around 1 year ago and applying it works wonderfully! In fact, most of the problems I am having is once I reach the "end result", aka when I have the girl in my bed.

I am not sure what's causing this, but no matter how hot the girl is or how horny I am during the pursuit, when it comes down to doing it I somehow stop being horny. Like, I feel no sexual energy and can't get hard, not even with blowjobs/handjobs.

This though passes the moment I get "familiar" with the girl. For example, I had sex with the last girl on our 3rd date, yet the very night didn't manage to do nothing... but in the morning we did it 3 times with no problems.

This is not the first time it happens. Actually, this happens with EVERY new girl I bed, it's getting quite embarrassing and it forces me to build mini-LTRs to be able to build familiarity with the girl so I can fuck her as I please - this has made one-night-stands basically impossible for me!

Is there a logical explanation why this happens? Like, I feel no shame or anxiety or anything, I just feel non-horny and can't really get exited at first, as tough my brain sees a stranger and does not want me to stick my dick in anything "strange".

I am 23 years old if that matters.

Thanks!

EDIT: I stopped watching porn 50 days before this.