Death and the EX

I know I haven't talked about my EX very often on here. Only as of recently. For reasons that should be obvious. We don't get along very well. I hold onto alot of anger from the things he did to me during our marriage.

Somethings are just not forgivable. Like Physcial and verbal abuse. Lets save that for another time shall me. (let me mention that this was my 2nd husband)

Anyways, I am civil when around him. That is just who I am. Its not fair for my kid to see the anger I'm holding onto.

Well shit I've gotten way off of the topic I wanted to write about.
Sorry for that.

So recently the EX's mother died. Which is very sad. No matter what I don't wish death on anyone.
The death of my sons grandma has really upset him.
Rightfully so , he was pretty close to her. No matter how old you are death is hard to deal with.
So I correspond with the EX, giving my condolence about the death. I ask if there is anything I can do.
Even though he is remarried. It really isn't my place. But I offered anyways.

So my son and I sit down and talk about the death. He cries. and asks me if I would go with him to the funeral. I'm torn between being there for my son and being someplace where I don't really belong.

So I contact the EX and ask if it's ok if I attend the funeral. Surprisingly he says, "yes".
My big issue is, should I really be there? He is remarried. What will his wife think? If his EX shows. Will she care? Should I not go?
I would be doing it out of support for my son.
It's soooooo complicated.
Any thoughts.