I (26f) love my partner (25m) and he loves me but sometimes I don’t feel desired?

My fiancé and I have a really loving, healthy relationship. We’ve been together for 3 years and we’re getting married soon. I genuinely know this man loves me with everything he has, which is why this is so confusing and painful for me.
Lately I’ve been feeling like he doesn’t really desire me in an intimate way anymore, and I don’t know if that’s actually true or if it’s just how it feels from my perspective.
The hard part is I can’t completely blame him because our sex drives are both a bit inconsistent and mismatched. We tend to go quite a while between having sex, and then when we finally do, it’s usually over pretty quickly. I often walk away feeling disappointed and still craving that connection.
I think the biggest difference is what sex means to each of us. For me, it’s so much more than just the physical side. It’s how I feel close to him, wanted, desired, attractive, and emotionally connected. I leave feeling reassured that we’re okay. Sometimes it feels like for him it’s more about relieving sexual tension, whereas for me it’s one of the biggest ways I experience love and intimacy. He says that it’s true for him too but I just don’t see it.

One thing that really gets to me is that I can be completely naked around him and he often doesn’t react at all. No comments, no flirting, nothing. I know people don’t have to react every time they see their partner naked, but after a while it starts to make me wonder if he even sees me in that way anymore. Whether that’s true or not, it’s how it feels, and it really chips away at my confidence.
We’ve talked about it before. He’s never been dismissive. He agrees that he wishes we had sex more often and says we should, but then life just keeps happening and nothing really changes. We probably have sex once, maybe twice, a month, and for me it just doesn’t feel like enough.
The thing that’s making me feel guilty is that I’ve started daydreaming about what it would be like to have a partner who actively desired me more. I miss feeling wanted in that way. I hate that my mind even goes there.
Has anyone else been in a relationship like this? Were you able to improve it? How do you stop feeling unwanted when you know your partner loves you, but the physical intimacy just isn’t where you need it to be?