Strong distrust in the other parent

My eldest son hasn't seen his dad since 2016, I remember that day well. There was a temporary active visitation court order I have sole custody, it was his weekend. I picked my son up, we went to visit my nana right after, hadn't seen her in a while, I was in college at the time living on campus it was an hour away from both his dad and my nana. I took my last final that morning after a night of cramming. Naturally when I got to my nana's I was tired I walked in, rubbed my son's back again and told him to go on have fun mommy was tired. Just as I was dosing off my nana shook me awake, she showed me wide belt marks across my son's back and I wasn't tired anymore. He was 5 at the time, he was scared to tell us his dad told him not to, my nana only came across it while helping him take all of his layers off, we were in Chicago, his shirt was attached to the hoodie and that's how she saw it. I called him he admitted to whooping him but denied causing the bruises. I was frustrated because the court order in place there was nothing I could do but report it which I did. The cops took pics and the detective was ready to go after him. Child services came to my nana's the next day, saw his bruises and said they can't go after a parent for disciplining their child they really called it discipline, I never hearheard from the detective after that, I called it abuse, luckily he stopped coming to pick him up and when it was time for mediation he didn't show up when the court found out he hadn't complied they suspended rights. My son is 10 now he's spoken to his dad twice since 2016, during the ft he couldn't even look at his dad, his voice would get low and his head would be down. He never wanted to talk to his dad only his cousin and grandma. He wants to go visit his cousin for the summer... when he said it my stomach started hurting. There is no way his dad would allow him to stay the whole time. He's one of those parents that have power trips when they have the kid I could be giving him simple instructions on how prepare his favorite meal he'd dismiss that and it'd be his way or no way. His reason for abusing my son the way he did was because he found him wearing heels and he didn't want him to grow up gay. My son is a nerd and I mean that in a good way cuz I'm a nerd his dad is materialistic and arrogant. He wasn't always this way neither was I, there was a time we were perfect for each other but we grew apart... far apart. My son wants to go see his cousin but specifically told me he wants to visit his dad for like a day then go back to his cousin. I explained to him it wont work like that I genuinely don't feel comfortable sending him. It's a gut feeling I have but to his side it's coming off as shady. Bottom line he's not going I seen the fear in him and I'm getting him some counseling.

Have you ever felt like this before? I'm not interested in anyone judging me, I know that how the world works. I just have this on my mind and no one besides my husband to talk to about it.