My question involves defamation in the state of: Montana

My Ex flat out lied on the stand to make me look like an irresponsible money grubber. My worthless attorney at the time was.....well.....worthless. As a result the Judge believed I came into the marriage debt ridden and my sainted Ex saved my bacon. This netted her unreasonable favor in the settlement. IMO.

She also said I was abusive to her and my child, no proof mind you that I had what she called a "hot temper" no police reports, and I have a squeaky clean background to this day. No bar fights, no traffic tickets for aggressive driving nothing.

Had I chosen to sue and prove I had no credit cards predating the marriage,(where she claimed all the debt came from) What would be the cause of action? Perjury? Slander? Defamation to the court? Defamation by Perjury?

How would one go about proving the negative on the "hot temper"? If I had cried foul and pointed to my utter lack of a record from birth to date and said she lied there was no abuse, would she have had to prove there was?

This is academic as the SOL has run and I couldn't sue anyway, Just curious.