Comon Law Marriage Requirements

What is the name of your state? Idaho
What are the qualifications someone needs to prove that a common law marriage existed? And what can be done to divide community property? My neighbor has been with the same woman for 18 years, and she has decided to kick him out. We have plenty of legal documents that she states that she calls him her "significant other". Will this be enough proof? Idaho has stoped common law marriage in 1996, but the paperwork ( a signed affidavit statment to a lawyer) she states he is her significant other as far back as 1992. Any help would be greatly appreciated as she will not give him any of his property.

The only thing that matters is who's name is on the title or reciepts

If its was PAID out of joint funds then it has to be divided equally. Checking, credit cards, savings, titles to the house car boats etc.

Then he has to sue her for his share. If she paid for everything then its HERS!