What do you think about supporting the husband whose wife cheated on him?
Why do you support him?
Because the husband is the rightful owner of the woman he married.
It's good to want to support your friend: cheating is wrong. But it's equally wrong for him to view wives chattel. It's not only immoral, but illegal in most countries.
Look it happens all the time, really!
It doesn't happen all the time. It is wrong to cheat, but also unacceptable for men to think of women as their property. Women have free will in this country and men need to respect that.