Simply put those who do are like the men who cheat, there POS who dont care about any other persons feelings. To them love is nothing, even after a long commited relationship at any point or cheating its the same answer, they just dont care any more obviously enough to keep to them selves. I recently got out of a relationship in which she ran off to texas and cheated on me, took her kids with her and disapeared after I helped raise them for a year. May not seem like much but it was gut renching considering I cant have my own.