My Wife Had an Affair With My Sister’s Boyfriend

she lied to me because of the fear that I wouldn’t want to marry her

How should I proceed with this…

Okay, my wife (Amanda) and I (Paul) have been married for 7 years.

Here’s the background of the story: In June of 2016, my little sister (Ginna) started dating a guy (Marcus), After 2weeks of dating, she asked for me to come meet him to see what I thought. Big brother checking on little sister stuff, we met, he’s good to her and everything is good. The same night that I went to go meet Marcus for my sister I met his new roommate, Amanda. Amanda and I hit it off very well and several months later we ended up getting married, we shared things of our past. She had just gotten out of an abusive relationship 6 months prior to July, she also explained that she has borderline personality.

Well, My sister inadvertently had seen some messages between Marcus and Amanda, joking about showering together and things of that nature. She confronted Marcus and Amanda about it and asked if there was a past, they both said no it was just joking and that they were just friends. (Side note they had been friends for 4 years prior) 6 months later when Ginna was speaking with a friend of Marcus’s, (Ron) he said that Marcus and Amanda had slept together.

Again, my sister asks Marcus why did Ron mention that, again Marcus says nothing happened and it was just a joke. At this point about 6 months into Amanda and my (Paul) relationship, I asked her if there was any basis for those claims. I explained that if there were history it was okay, that it was before we had met, and no biggie, just to be honest.

She responded no that she didn’t know why those things were being said and that there was no history and started to get angry. I left it alone but there were just some things not adding up. I didn’t want my overthinking to ruin our relationship so I left it alone.

Even though at times they seemed a little too close but just chalked that up to being long-time friends, specifically sitting next to each other with hands on thighs (hers on his) which seemed odd but didn’t want to come off as insecure an hour relationship so didn’t really say anything just noted it.

Amanda and I then moved to West Virginia for 3 years and after some questionable remarks made by The Neighbors while I was at work of Amanda becoming drunk and saying sexually inappropriate things to them. I asked her about them and was received with anger and that they were lying. Without proof I didn’t pursue it, at this point, it was just hearsay from the neighbor. I didn’t pursue it again because I believed her. We then move back to Virginia.

Fast forward 7 years later, Marcus and Ginna are still together, while Amanda and I are still married. We’ve all been friends and have all been our mutual friend group. Marcus and I have been working with the same company for 5 years now and have become pretty close friends.

Well 2 weeks ago, Marcus and Ginna broke up, for unrelated reasons. But we’re all still friends, my wife and he have regular conversations online and in person, and she refers to him as her big brother.

Well, 4 days ago she was online at 1:00 in the morning talking to him about him and Ginna breaking up. Which I thought was odd considering it was out of the normal for them to be speaking that late, mainly because Ginna would get jealous of them speaking so Marcus would either not respond to Amanda or would be very short and had been that way for several years, unless we were all hanging out., because Ginna was very insecure at this point based off Marcus cheating on her several years prior that they had worked through, kind of.

Well without any specific reason, I opened my mouth and said that I knew the truth about Amanda and Marcus. At this point, my wife started to get angry and then sadly admitted that she and him had been sleeping together before we all met. And that she lied to me because of the fear that I wouldn’t want to marry her. Even though in all of our prior conversations regarding the subject I had been more than patient and explained in the beginning that it wouldn’t be a big deal because it was before we met.

Now I am very unsure of everything else that she has told me about, especially based on her reactions in the past to things that she denied along with extreme anger. This makes me wonder if other things that I had asked her were also true and her anger is a sign of her being untruthful.

Alright, Paul, this is what it is, I’ll try to be as direct as possible. So, seven years down the line, and the past decides to crash your party? Here’s the drill: Yes, Amanda and Marcus had a thing before you two tied the knot. Now, this wouldn’t have been a problem if it stayed in the past, where it belongs. But, the truth has this funny way of digging itself out, and here you are, dealing with it.

I will start by saying that you feeling rattled is normal. Your trust took a hit, and that’s a tough one to shake off.

Amanda kept this from you, probably fearing it might change things between you two. And yeah, you said it wouldn’t have mattered, but she chose to hide it. That’s the part that stings.

Going forward, about those feelings of doubt creeping in, questioning if other denials were also cover-ups? That’s the trust issue doing the talking. When trust gets shaky, everything starts looking like a house of cards.

So, what’s the catch here? It’s time for a no-holds-barred, everything-on-the-table kind of talk with Amanda. Not just about her and Marcus, but about honesty, trust, and where you go from here. It’s not just about who slept with whom before you guys got serious. It’s about why she felt the need to hide it, why she doubled down on the lie, and how you both can rebuild what’s been chipped away. Listen to the whys, if you can work with them, fine. If you can’t, slide.

Remember, it’s not about pointing fingers or getting the upper hand. It’s about understanding, forgiveness, i.e., if you choose that path, and setting the ground rules for honesty going forward.

Surely, it’s going to be a tough convo, emotions will run high, but it’s necessary. You can’t move forward on shaky ground.

And those other doubts? Tackle them too. Not in an accusatory way, but in a “we need to clear the air” way. It’s about rebuilding trust, and that starts with transparency.

Truth is, Paul, this is about what you can accept, what you’re willing to work through, and what Amanda is willing to do to make things right. It’s a two-way street. If you both value the marriage and see a future together, it’s worth the effort to patch things up and reinforce those foundations. But it’s gotta be a mutual effort.

Take some time to process, and figure out what you need from this relationship, and what you’re willing to give. Then have that talk. It won’t be easy, but it’s necessary for whatever comes next, be it together or apart.

Good luck, man.