I knowingly hooked up with a married man today
why did you hook up with a married man?
I just wanted to have sex with him and didn't think about the consequences.
Did you consider STDs or how infidelity might affect his family?
Oh, I get it. You are trying to say I'm to blame if I help destroy his marriage.
Not necessarily, the marriage might already be on the rocks. Or they might be happily married with children. You don't know -- but it's particularly bad if it's the latter situation.