Is it normal that I don’t have sex as much ever since being in a relationship?

I (F23) spent my university years sleeping with random girls on a regular basis. I am talking multiple girls in a single week at times (I am “that” flavour of ADHD).

The only person I slept with more than once — regularly, in fact — is now my partner (21F). We had slept together multiple times when we were just acquaintances, throughout our close friendship, when we were just seeing each other, and maybe the first few months into our relationship being official. We’re now 2 years and 2 months into our relationship, and now we only have sex a once a month.

I am worried about what this means. I used to be very sexually active, but now I’m not. Even though I love her very much and I find her very attractive, I just have very little desire to have sex, just in general. I find just being in her company satisfying enough.

I’m getting worried that something is wrong because we don’t have sex as regularly as we used to. Is there something wrong, or is this normal? I’ve never been in a relationship nearly this long before, so I’m not sure.