Hopefully he won't become your boss.

Become the manager so you can have him work for you. Then you can fire him if he doesn't submit to your demands.

Heaven forbid that you become mature enough to work with your ex. It didn't work out, suck it up and move on. Ex-partners are only enemies if you make them into one.

I worked with my ex for 4 years and no matter how civil, it was still sort of miserable. It sounds like you're still hurt by the past. No matter how mature and civil you are around them, it's still difficult. Especially if it was a recent break up.

On the bright side, you'll have lots of opportunities to practice your professional demeanor.

My ex and I had to continue living and working together after we broke up. It sucked but it's called being an adult and acting professional. We actually did it so well that over two years later when I was moving away costumers were asking if he was moving with me. Best part is, despite the fact that we broke up because of some bad stuff, because of that we were able to stay friends. To this day we still play video games together online. That probably wouldn't have happened if we hadn't have had work to force us to act nice to each other. This may help you two get along better.

Now you have someone to sexually harass. That always makes work more interesting. ;)

Sorry OP I would hate if my ex was working with me... Well he was also abusive so that changes it a but but regardless hopefully you don't have to see him much.

This was after he knocked you up and threw you out, right?

maybe this meeting can be a good thing? idk. look for the fun in it.