You might be looking for the phrase "exonerating evidence".
Scapegoat - an innocent person made to take the blame for others
The adjective 'wont' does not need an apostrophe. The adjective describes a something as likely to do something or having a tendency to do something. Example: He is wont to blame others. The noun 'wont' does not need an apostrophe. The noun is a word for a usual habit or way of behaving. Example: He got up early as is his wont.The contraction won't does need an apostrophe, it's a contraction for 'will not'.
Such a person is a scapegoat.
No one to blame.
Would guilty be any help? Ex. You are the one to blame. You are the one guilty.
A person who consistently blames themselves for everything may exhibit traits of self-blame or self-criticism. They could also be characterized as having a tendency towards self-guilt or self-condemnation.
A few names for a person you blame your problems on are scapegoat or victim. In slang: Blame-y.
Scapegoating
Scapegoating
scapegoating
Scapegoating
Blame takers
If your partner is having an affair you should be having a conversation with them. You cannot place blame on the other person as they may have been lied to and may be the single one where as your partner is the one in a relationship, made the conscious decision to have an affair and is the one who is cheating on you. We tend to want to blame the "other" person when in fact the blame should be placed on your spouse. I can understand why you would want to but it would serve no purpose confronting the other individual and would just cause undo stress. If you plan on forgiving this individual you should talk to your partner and consider going to counselling together.
I wouldn't want to see you blame the wrong person.
blame....
Take what you said to your husband (because, you know, he's not without blame for this, either), and modify it as you see fit.
When people get a divorce that does not place blame on either person is called no-fault divorce!