My boyfriend feels "gross" after ?

talking to my boyfriend he says he feels tired (duh) and gross after . when i asked for him to explain. he said everything seems gross. this includes me but im the least unappealing, and hell still cuddle. i appreciate the effort and all, but this still hurt my feelings. but the real question is: does anyone else feel this way, or is there anyway to explain it better to me... im confused, hurt and frustrated because it makes him hesitant to initiate anything too.