I'm going to meet with my ex to talk about some issues he had during our relationship without telling my husband.
Why aren't you going to tell your husband about this?
I don't think he'd understand.
It is good to be concerned for others, but your husband should come first.   Keeping something regarding your ex from your husband can create a situation of distrust.
Just because I'm married doesn't mean I have to tell my husband everything.
It's true that you don't have to tell your husband everything that you do, but I think it would be wrong to hide the fact that you're going to be meeting with your ex. If your husband finds out that you've met with your ex, then he might think that you're doing something inappropriate, so I think you should be honest with him.