Shame on those who don't try their best to make a relationship work and justify themselves for cheating !!! Every religion teaches the values of relationships, rights of your partner ... I don't know why people don't read their books !!!!
Every religion tells you in one way or the other, that divorce is not good, it is the last thing if nothing else is helping !!!
And their is no space for cheating anyways !!! So you are at sin if you are cheating... think about it.

And yes, regarding those unmarried relationships (before marriage, lovers etc), they are meant to be a disaster as they are not right at the first place .... study your religion, no religion allows relationship before marriage !!

Adeel Ali