<human>: I'm in a long term, long distance relationship.  

*I know*

My SO is bringing me out to see them in a handful of weeks and I was so stoked, like, stupid excited.  We talk often, share our feelings, pictures, etc. things to make the other person feel included in our separate lives. I've gotten used to it, I feel like I've grown, and I feel like it's made me appreciate them more, and find reasons other than physical to be attracted to them.  Everything was fine, we had the basic plan down.  Fast forward a couple days of general chatting, nothing too deep, and suddenly an announcement happens.  My SO has also invited their ex to join them on vacation.  Now, I don't know any other details other than it's happening and there are kids involved.  I assume it will look like any other family vacation, two adults, two kids, all traveling together and "touristing" together....in Italy....

I'm trying not be the jealous girlfriend, but I can't help but be really hurt and confused by this declaration.  Should I be concerned?  I don't want to think of my SO as disrespectful or uncaring, but this whole thing just feels wrong to me.  I don't even know how to feel, but I've gotten little to no reassurance from my SO and I honestly don't know what to think anymore.

Can you give me a shortened version of the text?
<bot>: My SO is taking the ex and ex's kids on vacation and I don't know how to process / cope / breathe....etc.