In addition to Artur's point, I would affirm that yes, that is definitely the reason.

Every day without fail, there is a post in /r/relationship_advice that goes something like "My fiancee just sold my cat and wired all of my money to her secret boyfriend in Albertville. Am I right to be mad?".

I think it makes for an interesting discussion.

Maybe they do actually suspect they are a scumbag. It's a very damaging and pervasive mindset.