Why can’t i have random sex?

amarie • E.🐘 | 21.✨ | ♏️

I use to be able to have a night stand. But after being in a relationship for 4 years i can’t think about being with someone sexually it’s so weird for me & id feel like shit after. I did when my boyfriend and i had a break for a few months and i seriously cried and felt so dirty.. it made me miss my him after that. Why is this happening?