They might care in other ways but they don't care enough not to cheat. It's that simple.

If you don't talk about opening the relationship, you are breaking the trust, there's no excuse around it.

Okay cheater. Tell yourself what you have to.

"Honey, I've been cheating on you because I really care about you. I'm doing this without your consent or knowledge for our good"

Yeah, that sounds perfectly reasonable. /s

The mind games people have to play with themselves to feel better about doing shit things...

100% chance this guy/gal has cheated on their So at some point and used this exact reasoning to convince themselves it was OK lol