Was I wrong to put my son into therapy despite my ex believing that he doesn't need it

So to start off our son is 7. He's been having issues at school recently, more specifically, he'll get in trouble for something super minor and he just completely shuts down. The first episode was towards the beginning of school, and he hadn't done something in class so as a consequence he lost his Chromebook that had games he wanted to play. When the teacher took it away he hid under his desk, began to cry and refuse to communicate. Later that day he came home and I tried to help him with his unfinished class work. He expressed that the work was too hard, he was stupid, and he wanted to change schools "because another school would be easier". I called his father and asked him to help me comfort and encourage our son and he remained silent until he hung up. It felt like I was speaking to a wall. This is a normal reaction from my ex.

In a separate incident, I received a call from the after-school program stating that my son had thrown another student's pencil and after being told that wasn't okay, he once again shut down. I ran down to the school to figure out what was going on, and the teacher tells me that it wasn't a big deal and that the other students had already moved on with their day but my son refused to talk to anyone after the incident. He wasn't even in any trouble. When I was finally able to get him to talk, he expressed that he was afraid he would get his privileges taken away, and that was the reason he completely shut down. I explained that it wasn't a big deal but reiterated to him that if it were a big deal that his actions have consequences and this shouldn't be something that scares him like this. He said that he understood.

Recently, my sister her daughters came out for a visit that he was very excited for. We all went to a family friend's place who has a private lake. My son refused to play with his cousins and sat on the sidelines despite everyone encouraging him to have fun while his cousins visited. He remained standoffish and upset, but finally got in the water with his cousins and seemed to have a good time until it started to get late and we had to leave. He then began crying that he didn't want to leave and he wanted more time to play with cousins.

This is all very new behavior from him. When I spoke to my boyfriend, he told me as a child he went through divorce and separation and suggested that my son may be still dealing with his father's and I separation. It's been 3 years since we separated, and we didn't separate on good terms. It was a DV situation and I was able to escape when he punched my mom in the face and was consequently jailed.

I called my insurance company and explained the situation so they put my son's case through a screening and the result was we were approved for therapy. While filling out the therapists paperwork it mentioned that the other parent of a minor should know that the child is being placed in therapy. So I texted my ex and explained that our son was having behavioral issues so I took the initiative to get our son into therapy and that I genuinely believed that it would benefit our son. He responded by saying that our son didn't need therapy, that it was my fault he was acting out because he's in the after-school program and don't spend enough time with him. He then said I don't discipline my son. This was all very frustrating as it felt like he was pointing the finger at me, when all I was trying to do was help my son. I'm I overreacting here? Was getting my son into therapy wrong thing to do?