I guess we'll all just have to agree to disagree on the whole "homewrecker" thing.
The way I look at it is this: if someone knows that another someone is married and they engage in an intimate relationship with that person, then they are hurting that person's marriage (i.e., wrecking the home). The married person engaging in the adulterous activity is also wrecking the home. They are both guilty. They are both homewreckers.
However, if the unmarried person is unaware that the other person is married, then he/she is not guity. He/she is a victim as is the unwitting spouse.