got married in 1997, never divorced and he married another women
Since you were never divorced, there will be issues regarding assets that you and he have accumulated since your marriage. Either of you may have retirement funds, a house, savings, etc. It would be best to consult a family law attorney. Mr. Leroi is correct- if you don't want to be married, you need to file for divorce. His "marriage" to his current wife is not legal.
He has committed the act of bigamy in CO. You can report it to law enforcement and the local DA. However, it is doubtful that they will want to get involved and I do not know one single occasion in 21 years of practice in which someone has been charged with bigamy.
Your better option is to file for a divorce. CO is a no fault state. So, his marriage to the other woman will have very limited value. However, you obviously do not want to be with him anymore and should simply make it official.
I assume that you have been physically separated for some time. This can create a lot of risk as, despite the way some people act, marriages do not simply expire when you are separated long enough. The mess your husband finds himself in is only one of many. He is guilty of a felony if a prosecutor is willing to pursue it and his current marriage is invalid. Additionaly, any debts or assets you acquire are subject to being split with the other spouse and if either of you becomes disabled the other may end up paying spousal support despite years of separation.
The best thing you can do is to file for divorce. It sounds like it is past time for the marrage to be over.
I agree with the answers already provided. In addition, at this moment, if you want to do nothing, you may choose to do nothing. The benefit may be that if your husband dies while you are still the spouse, and there are any benefits to go to the spouse, then you would get them and the new wife would not. HOWEVER, there is a big risk too!! If your husband incurs debt, especially medical debt, then you may be held to be jointly responsible for that debt. You could end up paying attorney fees for a man from whom you've been separated for many years.
I suggest you look into filing for divorce. It appears that he would want to be divorced as well, so if he will sign all of the papers with you, it can be a pretty quick (just over 3 months) and easy process. You don't state whether you have any children with this man, but if so, support issues would need to be discussed.
Divorce is the process of formally ending a marriage. Divorces may be jointly agreed upon, resolved by negotiation, or decided in court.