If you know, or strongly suspect that your partner is having an affair, the sooner you confront him or her, the better. Angry or hurt as you are, the way you handle the confrontation carries a great deal of importance in whether you will be able to work through this obstacle and repair your relationship. Be direct but not critical. Don't ask, "Did you have an affair?" (That leaves more chance for denial.)

• First, validate him: "I know you've been lonely. I haven't been there for you, and I know there's someone else."
• If he admits it, ask: "Can we talk about it?" and "Can you leave her?"
• If he doesn't admit it, say: "I don't want to get into a power struggle over whether you are or aren't. I just know there's too much distance between us, so there might as well be someone else. We need to get help and bring back the intimacy in our relationship. I want to work this out with you."
• 9 times out of 10, if you make him feel safe and don't judge him or get angry, he will admit the affair. He's feeling guilty and wants to be relieved of that burden.
• Make it safe for him to admit it. Say, "Let's work it out." Then allow your partner to speak and remain calm and listen. If you get angry, start crying, or attack him, you won't find out what you need to know.
• Anticipate that your partner might lash out at you, accuse you of betraying him, or throw up other non-related issues. Keep bringing the focus back!
• Express your suspicions despite the fear of abandonment. Avoiding the issue condones the affair and increases the chances of a break-up.
• Be compassionate. If your partner is cheating, he or she is probably in a lot of pain too.
• Do not threaten to call a divorce lawyer.
• Insist that the affair end, otherwise there is no hope of repairing your relationship.
• Don't try to forgive prematurely. you will need time to grapple with your anger, hurt, pain and remorse
• Reach out-reconnect with parents, siblings, friends. If you are a Pursuer, you are likely to feel isolated and it is crucial for you to take your loneliness back to the family you grew up in and deal with the betrayal.