Oh S, this must be so hard for you. But really, dont call. It is not a good idea. If your h finds out, he will be very angry. I know he acts like a teenager, but he is a grown man and you cant interfere with his life.
Hard as it is, you have to let this one go. All part of the journey. You cant stop him from seeing who he wants. If not her, it might be someone else.
Sorry this is so hard. It just sucks all the way around.
