Anxiety about taking my son out

My son is 7 and has got quite a bit better over the past year with aggression towards other children but it can still occur. The problem is I still have so much anxiety with taking him out to parks etc with my 3 year old as I worry that he will become aggressive and I won’t be able to calm him down or remove him from the situation as I have my 3 year old to also attend to.

I feel quite sad that we don’t often do anything when I don’t have my husband with me to help as I honestly get so anxious I just can’t face it after all the incidents we’ve had in the past :(  The anxiety is overwhelming whenever I set foot in a park and I just can’t face it (I won’t even contemplate soft plays as I can’t continuously keep an eye on him).  As I said he has got a fair bit better but I think it’s more my anxiety about it all stopping us more than anything... although I could be wrong and I guess I’m not willing to take the risk :/ 

Just wondered if anyone else feels like this or has any advice, hope the rambling post has made sense