The type of people who do this usually have a history of doing this, and if you look you'll find that they've done this before, probably more than just once or twice; and it’s only going to be a matter of time before they do the same thing to the person they're with now. History repeats itself with them, because they are the common denominator! The saddest part of all of this though, is that it's probably led you to begin questioning your worth, and the value you bring.