What MickeyCheeky said. @
MickeyCheeky
I think its important to talk to your partner about this. I'm not sure how to go about telling you how. It sounds like you are hesitant, and maybe worried about their reaction?
I personally don't think we should have to force ourselves to have sex when we don't want to and are uncomfortable. On the other hand, I think what some of the other posters said is valid. If you feel comfortable and happy to please your partner even if your not "as into it as they are" that's ok. Maybe seeing a sex therapist or relationship therapist could be good down the line.
I wish you the very best with this. I'm glad you reached out here on relationships forum.