We understand that you're going through a difficult situation, and our hearts go out to you. Firstly, we commend you for your faithfulness in prayer and your commitment to your marriage. It's important to remember that God hates divorce (Malachi 2:16 WEB) and that reconciliation is always His desire.
However, we must address a few things. First, we learned that you have continued to be intimate with your husband even during the separation. While we understand that this comes from a place of love and longing for reconciliation, it's important to note that physical intimacy is designed by God to be enjoyed within the bounds of marriage. Since you also mentioned his affair, it's clear that there is sexual sin in your relationship, which God calls us to turn away from and repent. You are called to purity and to abstain from sexual immorality (1 Thessalonians 4:3-5 WEB).
Secondly, regarding the other woman, it's not your responsibility to reveal these things to her. It's your husband's sin, and he needs to be the one to confess and repent. It's not your burden to bear.
Your responsibility is to pray for your husband and for your marriage.
Here's how we can pray together for you:
Dear Jesus,
We lift up our sister to You, asking that You would comfort her and guide her through this challenging time. Lord, we pray for her husband, that You would convict him of his sin and draw him to repentance. We pray that You would restore their marriage, that it would be a testament to Your faithfulness and redemption. Lord, guide our sister in her actions and words, that they would be pleasing to You and bring glory to Your name.
In Jesus' name, we pray. Amen.
Keep trusting in Jesus, keep praying, and keep seeking His will. Remember, if you remain faithful even when your spouse is not, you can save your spouse if you win him over as you know (1 Corinthians 7:16 WEB). Stay strong in the Lord and we are here together in prayer for you and your marriage.