Anecdotally, it's the opposite for me. When I'm in a relationship my sex drive is a lot higher, and since sex becomes more part of daily life, sex starts colori

Anecdotally, it's the opposite for me. When I'm in a relationship my sex drive is a lot higher, and since sex becomes more part of daily life, sex starts coloring things a lot more almost unconsciously, looking at other women more sexually, thinking about it more etc. If I'm single I usually just focus on me and my projects and sex kind of fades away into the background. However, multi year, really long relationships I could see your testosterone and sex drive drop off, as the excitement of it (neurotransmitter-ly speaking) wears off.