2 years

My boyfriend & I are about to hit 2 years of being together. We have been having sex for about 20 of the 24 months, & I feel like he isn't as interested in me unless we are having sex. I love sex with him & we have only ever been with eachother & plan on keeping it that way, but I feel like he isn't as interested in me or trying as hard to make me happy or woo me. I'm starting to feel neglected & like we are in a routine. I don't want to be upset with him or disappointed or feel depressed but I do. I'm not sure how to handle explaining this to him. Any thoughts?