Your saying that as a women also some people enjoy the novelty of new partners, the same partner can get boring over time, and also carries responsibilty of being in a relationship, having hookups with no strings is easier and less time consumingSex with someone you love and who is also in love with you is way more fun and pleasurable. There have been surveys and studies on this. A romantic partner will wanna make sure you have the maximum pleasure,whereas a random hookup won't care about your pleasure.