<human>: Can you give me a shortened version of the text?

My ex and I were together for almost eight years. We broke up a little over  three months ago. It was mutual, amicable, and we still remain friends but with fairly low contact.

I've recently started seeing someone else (not quite relationship-status, but definitely the potential for one). My ex knows that I've been dating, and he's cool with it, but he doesn't know that I've been getting relatively serious with someone.

My birthday is coming up, and I'm throwing a huge party. My new guy is coming as my plus one, and is really excited to meet all of my friends. The problem is that my ex will also be there. I don't want him to walk into the party and be blindsided by me making out with or dancing with or hanging all over with some dude. I just don't want him to be caught by surprise.

How do I go about telling him that I'm seeing someone else? Should I even bother? What do you guys think?
<bot>: I'm dating someone new and don't want my ex to find out by accident and be hurt. How do I tell him?*