When It Feels Like I'm Not Enough

I've been with my partner for three years now. We're happy in many ways, we support each other, share our hopes and dreams. But lately, there's this thing that's been eating at me. During intimacy, it seems like he's not as engaged or excited as before. I try to bring up fantasies, suggest new things, but it feels like the spark has dimmed on his end, even if I still feel passionate about us. Sometimes, I worry maybe it's just me and how much I want him to enjoy himself too that makes me think something is wrong. But there are moments where he seems almost distant or distracted during our intimate times together. It leaves me feeling unfulfilled and wondering if this is normal, or if there’s more to the story than what I'm seeing. Does anyone else experience similar feelings in their relationship? Am I overthinking it, or could there be something deeper we need to address?