AITA for causing my son to lose his child?

Throwaway due to how sensitive this topic is and not wanting to be recognized

My son and his gf had been together for about a year when she became pregnant accidentally. My wife was thrilled because she was looking forward to being a grandmother. He decided to stay with her, but a few days later began hanging out with his ex. We know because she lives nearby and I have seen them together. I confronted him and he said his gf is ok with it. I don’t believe it as they are still together. But I’m old and I can’t really fathom what that kind of relationship would look like.

I’ve been cheated on and it was a huge betrayal that I haven’t forgotten about. My wife told me to drop it but I just didn’t believe him when he said they decided to open up the relationship. I decided if she knew then if I asked her about it then it wasn’t a big deal.

I asked her if she was ok with an open relationship with the father of her child and she had no idea what I was talking about. I realized she had never had that conversation with him and admitted I had seen him with his ex and he had told me she was ok with it as they had opened up the relationship. She began to cry and left. A few hours later I get a call from my son who was screaming at me for interfering with his relationship. My wife is also extremely angry with me saying I was jeopardizing our chances of being in our grandchild’s life.

Long story short they broke up. She moved out of their place to her parents house. It’s been a few weeks and a few days ago she told my son she had an abortion and so they had nothing to do each other anymore and to never contact her again. My son and wife know it’s my fault and say she wouldn’t have found out if it wasn’t for me. My wife has brought up divorce, saying I’m not loyal to my family so how can she know I’ll be loyal to her. I’m so sad about how it ended and I’m regretting saying anything if this is the results.