Yep, no victim, no crime.
I agree. But just because something isn't a crime doesn't mean it's not immoral.
True, but good luck arguing that something is immoral without a victim, either.
What about cheating on one's boyfriend/girlfriend? What about yelling at your children? What about spreading false rumors about somebody else?
Cheating on one's boyfriend/girlfriend is a violation of trust, because you have broken the agreement that you had with them of being mutually exlusive lovers.
Yelling at your children is emotional abuse. Stefan Molyneux has some excellent podcasts on that.
Spreading false rumors about someone else is slander and as such damages their reputation. In this case you are committing fraud, which is considered force