feeling used but i love them

my partner and i have this thing where we do kink stuff sometimes. it's all consensual and fun when it happens. but lately, they've been asking for more hardcore stuff that makes me feel a bit... dirty. one night, we did this whole roleplay where i was supposed to be their submissive sex slave or something. it made me so fucking wet though, even as i felt like a stranger's hands on my body. after, i just laid there feeling empty inside. they were laughing and seemed happy but i couldn't shake the feeling that they only want this part of me for their own twisted pleasure. we cuddled up eventually and all was quiet again. but i'm stuck with this lingering sadness, wondering if it's worth it to keep doing something that makes me feel so used sometimes.