My husband and I have been together for 18 years, married for 12. We have two children, aged 15 and 13.
Years ago, long before our relationship, when DH and his female 1st cousin were teenagers, they had a brief, secret relationship with each other.
At first, I thought they just slept together, but over the years DH confided in me that he had slept with her once while staying at her house for a week during the summer holidays when they were both 16, but that they also wanted to be together but knew they could never tell anyone.
They lived in different parts of the country and rarely ever saw each other.
My DH has told me he's actually quite angry with his parents for putting them in this position. They were teenagers, who didn't grow up together, rarely saw each other, and yet when the family would meet up once or twice a year, they would always stay over and the kids would be put in the same room, on bunk beds and camp beds, without any thought of the fact that they were developing and going through puberty, just assuming they were innocent kids. He says the curiousity and strong feelings were inevitable and his parents and other adults should have been more responsible.
Anyway, noone at all knows what happened except DH, the cousin, and me.
When they reached young adulthood, the cousin emigrated to a different country and DH and I have only seen her twice in the last 15 years.
However, we are all currently all Holiday together! MIL recently won a large amount of money and took the whole extended family, 17 of us in total, away on a huge Holiday. Cousin is here.
We have been drinking every night and cousin, who is now in her late 30s, and doesn't have a husband or kids of her own, keeps relentlessly saying flirting with DH. Telling him he looks great in shorts, whistling when he takes his top off on the beach, making silly sexual jokes, and hugging him by coming up behind him and resting her head on his shoulder. Noone else seems to notice and DH says not to worry about it as he doesn't feel anything for her and nothing is going to happen and she's just being playful.
But I've noticed she's not like it with any other males here. Just DH.
The final straw for me came last night when she sat on DH's lap while we were all sitting around drinking and put her arms around his neck, and kissed his cheek.
DH just laughed and told her to get up then got up himself and went to the bar.
Again, we had all had quite a lot to drink.
A few minutes later, I went off to the toilet and she was coming back towards me. She was quite drunk and came over with her arms out in front of her to give me a hug. I stepped away and looked her right in the face. I said "Stop flirting with my husband. Don't think I don't know your history. If you come anywhere near him again, I will tell everyone about you two." She looked utterly shocked. I walked away. She must have gone straight to bed.
Today, she's been really quiet all day. Everyone's commented on it but they've just assumed she's really hungover.
MIL and I were sitting on the beach and she commented that this trip has been good for her. She's had a hard time lately as a bloke she was going to marry cheated on her with his ex wife and then went back to her. She's really benefitting from being with family to support her as she's so alone out there.
I feel really guilty for saying that to her last night. I just got so jealous seeing her sitting in his lap, looking amazing in her tiny sundress, knowing their history and she was probably his first love, and felt so insecure. The stupid fling they had was so long ago and they were young and I know at least DH deeply regrets it and is embarrassed about it.
I'm worried I've now ruined her holiday. I didn't know she was going through that. I've been chatting to her to be friendly and get to know her but she never mentioned it
Was I unreasonable?