Friends with benefits are friends who add sex and try to keep the friendship as the main plot. The arrangement works when both people can tolerate the other dating, not dating, and sleeping through a text. It fails when one person uses friend as a waiting room for a title that will never be offered.

Rules need saying: overnight stays, birthday parties, what you tell mutual friends, condoms, testing. Jealousy should be treated as a stop-and-talk, not as a personality flaw to hide.

Ending the sex and keeping the friend is possible and awkward. Ending both is also possible. Ghosting a friend because the benefits got complicated is a small cruelty that spreads through a social circle.

If you already want a relationship, say that before the third sleepover. Hope is not a contract the other person signed.