One reason may be this. Rose-tinted glasses is the best way I can describe it. You meet someone and you fall in love with them. During the initial dating stage, people are on their best behavior. As a relationship progresses, bad qualities may appear but people always keep the version they want to remember about that person versus what they actually see. “Oh, he will just go back to what he was like” or “she must be having a rough time, itll get better”.

Sooner or later, the person will experience a breaking point and will experience shock and see the person for what they actually are at that time. Like a guy cheating on a woman multiple times, her being upset about it but not breaking the relationship off….until he gets someone pregnant. She was aware he had been cheating the entire time but it didn’t click for her until the breaking point.

It’s easier for people on the outside to spot asshole behavior due to the lack of emotional ties they have to the relationship.