If you do not agree to a divorce, there won't be a divorce. That's how ROC family law works. Also, you will need 5 years of cumulative residence on a spouse-based ARC within the last 10 years, with 183 days of cumulative residence in each of these 5 years.
That being said, you should see how many months you have left until you qualify for an APRC and not sign / agree to anything before that.
Do you have any evidence for your spouse's infidelity? Adultery is a criminal offence under ROC law.