'My cousin just told me she saw my fiancé kiss my twin sister.' UPDATED

"My (28F) cousin (22F) just told me she saw my fiancé kiss my twin sister."

I (28F) really need some advice. For some backstory, I am engaged to my longtime partner (30M) and am in the process of planning our wedding. My fiancé and I are at our family’s lake house for a week long family reunion. I’ve been super excited for this trip to have a much needed break from work and wedding planning and also to have a chance to see all of my aunts, uncles, cousins, etc.

This morning, my cousin (22F) pulled me aside and told me something completely unexpected. She said she went upstairs to grab some clothes and as she was walking down the hall she saw my twin sister and fiancé talking quietly in one of the bedrooms. Then she said she saw them share a quick kiss.

I am in shock. My twin sister and I have always been so close. My first thought was that there’s no way this happened. I have never seen or noticed any tension between my fiancé and sister and they also have limited opportunity to be around one another. We live about an hour from one another and are busy with work. I cannot imagine that either of them would do this.

I’m also wondering what to believe of what my cousin told me. I have no reason not to trust her, but I just want to believe that she saw something wrong. Idk. A kiss is hard to mistake.

So I am currently “resting up” as I have “period cramps” and don’t feel well. I asked my cousin to keep this to herself at least I can figure out what I want to do. We’re all staying here together for the week (until Sunday). If I confront them now I know this would cause a huge scene. However, I don’t know if I can wait until we get back home knowing I’m just festering inside with this knowledge.

So I’m here turning to the internet. I don’t know if I need advice, am looking for support, a rant, etc? I suppose any advice or comments are appreciated.

Edit: We are fraternal twins. No chance we could be mistaken for one another.

Any advice? This is what commenters had to say:

maisellousmrsmarvel said:

Bring your cousin, sister and fiance all into a room and say that your cousin saw them kissing and is this true? Someone is lying and seeing all of their reactions at once should tell you who.

YMMV-But said:

Don’t confront. Just talk. Ask your fiancé today. Otherwise you’re just going to stew about it. If it causes a big scene, let it. Better to talk it through early & get the truth before it builds up into an even bigger deal in your mind.

PlaidyLady said:

Ugh, please dump the trash fiance, and go low or no contact with your awful sister. I'm so sorry. Take care

They are bad people.

And Cold_Confidence7288 said:

Me personally, I’m bringing this up while all parties are at the same location. Not necessarily literally together in the moment. But if it brings drama, so be it, not your fault. I’d want it sorted.

She later shared this first update:

To those of you who were requesting an update, here goes. After going back and forth on whether I should try to snoop through my fiance's/sister's phones or just sitting everyone and asking, I decided I would go through with the latter. My cousin actually came back later to my room to check on me and we had a brief conversation.

She let me know she supported whatever my decision was and she would be there to back me up if I needed that. While sweet, it kind of squashed any thought that my cousin could be manipulating the truth. And honestly, after that conversation with her I couldn't keep holding this in.

I got the four of us together and laid it all out there. I told them that my cousin came across them talking in the upstairs bedroom and witnessed them kissed. Whoever told me to tell them what I new and then zip my lips, thank you. I didn't even have to ask any questions but I could see the guilt flood over my sister.

It seemed like my fiance was trying to find a way to backtrack, but then my sister started profusely apologizing and crying. While she's crying my fiance tells me it was a mistake and only one kiss.

This is where I said I wanted them to show me their phones and if it was only one kiss I shouldn't find anything. My fiance hesitated again, but I told him we would be done if he didn't let me see it. From what I could find, my sister started flirting with my fiance, starting off with compliments. I don't know if she was just stroking his ego, but their texts very much so were flirty in nature.

Up to this point, I am pissed but unsure what this means for our relationship. Until I get to one of their last messages that was sent this morning from my fiance saying "I know I should regret that, but I don't."

I told him to pack up his sh!t and we would talk about this at home. I told my sister I was disgusted and she should leave me alone. So I haven't technically called anything off, but I'm going to take the next couple of days to really sit with things. I can't imagine being able to go back to him after all of this. I feel sick.

I don't want to be anywhere near my sister, but I would rather be here to have space from my fiance. I think right now I haven't truly processed what this means as I am seeing red. As mad as I am with my fiance, I feel so betrayed by my sister that has quite literally been with me through all of my ups and downs.