I am going to keep this as short as possible. When I (36f) first moved to my state three years ago, there was a child in the area that was about my son’s age. For the first year, the child’s mom (32f) and I tried to be friends. We hung out a couple of times without kids, but we really didn’t have enough in common to click. Over the past year and a half, we have only seen each other about 5 times at various birthday parties and events. We were always friendly and considered each other friends. But, several of my texts went unanswered, which didn’t really bother me. I figured our friendship had evolved to its final state of mom friends who hugged at birthday parties and forgot each other the rest of the time. This mom, who I will call Nancy for the sake of this post, has only one child with her ex. Her and her ex, “Andy” (33?m), have been split since their son was only a few months old, over 5 years ago. In the beginning, their relationship was contentious. She explained that he was emotionally abusive and would get very angry and she could not be in a relationship with him. She talked excessively about how hard she worked at getting over him and has been in and out of a few relationships since I've known her. About 6 months into knowing them, Andy started coming to birthday parties and other events. During this time, my husband (40m) got to know him a little. They have quite a lot in common. They work in the same field, love to hike and off-road, and are both members of a widespread duck vehicle cult. Today, my husband and Andy decided to get together and head into the mountains to do some off roading with our sons. (Sons are 5 and 6.) When my husband first mentioned these plans, I went to text Nancy about it. She had recently gotten back from a trip and I texted her asking how it went and she never responded. When I remembered she doesn’t often respond, I decided to not bother. This morning, when my husband left, I texted her what their plans were. Just seeing if she would respond. I was excited about the boys being able to see each other. And she did respond. She wrote several scrolls worth of text, basically saying I have betrayed her by allowing my husband to hang out with her ex. That I am not a loyal friend and she can no longer speak to me. She said that she considered my husband and I as one person, and that his hanging out with Andy is a betrayal on my part. "It feels like a betrayal that you or your husband (I see you as one since you're married" would want to entertain/foster any kind of relationship with my ex." I can understand having big feelings about this to an extent. But not so much to completely attack my character. So, am I the asshole for "allowing" my husband to hang out with a friend’s ex ?