Nah, it's not entirely wild. I see life is finite, when you die, that's it, nothing follows it. So if someone does something that has a permanent impact on your life, like betraying your trust such that you can never trust anyone ever again, forever plagued with being jaded, your life has been forever marred, you can't get that back, it is a form of killing, imo.
Obviously it's not outright killing but consider this, if I outright kill, that person is dead, they can no longer experience pain, bad thoughts, nothing, me destroying your trust can follow you until the end of your life. It's like rape, etc., anything that causes a traumatic experience that follows you for life, your life is forever plagued.
On the rate of cheating, yeah, a lot of people do cheat, they are all trash people with no care for next person, no integrity, and act on impulse. There is no excuse for it beyond the recognition of the level of depravity that follows most humans.
I take ethics very seriously, these matters very seriously, but I can understand why it might seem so inconsequential without a foundation based on ethics, but it's also why we run into so many issues involving humans today. I can put you on some solid reads if you want.