AIO for feeling frustrated about the mismatch in sex drive with my partner?

My partner and I have been together for a while, and we have a great relationship overall. However, our sex drives are completely different. I have a much higher libido and often feel rejected when they aren't in the mood. I’ve tried to be understanding and not pressure them, but it's starting to affect my self-esteem and our connection. Whenever I bring it up, they say I'm overthinking it and that sex shouldn’t define our relationship. Am I overreacting by feeling like this is a bigger issue than they think?