Even though it hurts to write this, I really need some help.

I walked in on my mother-in-law and my older brother kissing by accident while we were all together as a family. You read that right. My brother is seeing my mother-in-law, who is married to my husband. To put it mildly, it was shocking.

She had my husband when she was very young, and my older brother, who is 11 years older than me, is only 6 years younger than her. However, don’t jump to any conclusions just yet. So there isn’t a big difference between their ages.

But what my brother said when I told him what was going on made me feel even worse about it.

When I told my brother what I saw, he told me that they had fallen in love a few months before when they ran into each other at a café. He told me that they were both single when they met, so their relationship shouldn’t really have any problems. Because they were afraid of what their family would think, they kept it a secret. That’s why I didn’t know about it until now.

He also made it clear that he and she want to keep dating. He said sorry that he didn’t tell me, but not that they were together. He also told me not to tell anyone else until they were ready to tell the rest of the family. That was the worst part.

It’s hard for me to keep all of this in my head. In some ways, I feel bad that I haven’t told my husband about this secret. He has a right to know what’s going on, especially since his mother is involved. On the other hand, I’m having a hard time accepting their relationship. It seems… strange, you know?

I feel like I might be a bad sister for being so critical. I should be happy for my brother, no matter who he’s dating, shouldn’t I? Also, if I decide to help them, should I tell my husband what I know or follow my brother’s advice and keep it to myself?

I’m confused and lost, and I need some outside help to see this clearly. We would really appreciate any advice or ideas you could give us.