I wish that you will know what it mean when you partner cheat on you if you think that being against cheating is bad
cheating is bad, but to say cheaters don't deserve to be happy is extreme.
in this case I feel that considering we are dealing with a comphet young girl who knows little in the way of romance and is confused about what shes wants in a relationship, I find it is expected that she will end up stepping on a few toes or making mistakes like that.
and honestly it's probably better if someone cheated on me and ended the relationship if it already wasn't going well... even if dialogue would've been the better option.
tldr people tend to have a justfiable/pitiable reason for doing something bad, and they still deserve the chance for redemption and a chance to be happy.