Lost & Found

Recently Ive caught up with a friend I have not kept in touch with for 7 years. Turn out most of our friends have settled down with their bf/gfs from university. I wonder if these couples did indeed "settle" down for companionship sake or love? I remember a couple of my gfs got hook to new bfs in less than a month after they have broken up with their exes. Is it a question of loneliness? the need to be loved or?..