That's something that happened in junior high, I don't see myself getting physical now that I'm older.
Let's say I walked in on them in my bedroom, I might lose my temper and it could get physical, if it did I'd beat them both.
If I was hurt during a mutual fight then I'd deal with the consequences. If the situation was one that I was unknowingly targeted by my husband's mistress and disfigured, they both better hope the job got finished because I'll be coming for both of them.
The above situations are completely hypothetical, I don't know what I'd do until the time came. I'm not a violent person, I'm just too old. At this time there just isn't any reason for me to have to go to jail. But if I go, it's because I weighed out the risk and found it to be worth it.