I suppose hook ups might be psychologically rewarding for those who have been tremendously inhibited or emotionally clamped for years. Extreme religious can produce this effect upon young people. A period of relationship free sexual activity may lead to a sense of freeing up the feelings. For some it could lead to an underlying insecurity in relationships with a subconscious question in the mind Will it last?
That question could sour a future relationship as the other person would sense a lack of trust. Treat hook ups as an adolescent episode, an experimental period and just pray that there wont be any disaster as result of it.