My cousin said nothing but horrible things about her boyfriend since arriving for the weekend. She told me how he likes to know when, where, and with whom she will be drinking, as he is straight-edge and disapproves of alcohol. I saw for myself how upset he got over text when she waited longer than 30 minutes to respond to his messages. This level of jealousy and insecurity was not good, and it was made worse by the fact that my cousin was subconsciously distancing herself from this guy without actually breaking up with him.
My cousin and I grew up together. Our lives practically mimic one another's, except when it comes to how we manage relationships. The minute I realize that a relationship is doomed, I dump the guy. She however rides out the worst of relationships until he dumps her. These differences can be described in terms of survival strategies. If we were both stranded on an island, she would be the one who resigned herself to life on the island while I would try my luck at sea.
For all of her boyfriend's faults, my cousin was the one with the underlying problem; she is too nice to break up with a guy. She does not like to hurt guys no matter how awful they are. She hangs on, hoping the relationship will improve or that she will get dumped and walk away guilt-free.
Life has the possibility of ending every second; why waste that with someone you know is wrong for you? Not only are you wasting your time, but your partner's time as well. You could both spend that time getting over the failed relationship and meeting new people. While you may hurt the person's feelings in the short term, you will save them, and yourself, weeks, months, or even years of torture.
Fear is ultimately what keeps us in doomed relationships. Our fear of hurting someone, our fear of being single, or our fear that we might not find someone better. Fear is never a good reason to stay in a relationship. No one ever says, "We decided to get married because we were too scared to break-up."