I recently got divorced and after going to counseling at our church to resolve our issues (which did not work) the counselor who is a pastor there said that based on Mathew 18:15 my now ex-wife would be excommunicated from the church because she knowingly committed a sin by divorcing me and not following the advice given in the bible. It’s true, she had no biblical grounds for divorce, but how does Mathew 18:15-17 apply?
According to Matthew 18:15-17 if you failed to convince your ex-wife she has sinned against you, first by explaining your position face to face, then in the presence of witnesses, and finally in front of the church, you should treat her “like a pagan or tax collector.” In other words, like an unbeliever. 1 Cor. 7:15 says if an unbelieving spouse wants to leave the marriage, the believing spouse should not try to prevent it and is not bound in such circumstances.
I would also caution you to follow the advice of Matthew 18:22, forgiving her up to “seventy times seven” times. In the Parable of the Unmerciful Servant (Matt. 18:23-35), the Lord said your failure to forgive your wife for this thing after the Lord has forgiven you for everything could put a strain on your relationship with Him and at the very least cause you to miss out on blessings you might have otherwise enjoyed. Your ex wife’s sins are between her and the Lord. You need to be careful you don’t commit the sin of unforgiveness.