Ex is my reporting manager?

He proposed me nd I rejected. Then I proposed and he rejected. Both of us had huge ego. I hooked up, he became mad and things ended. He was never respectful or kind.
Last week we were together for 5 hrs sitting next to each other and both of us didn’t talk and I could see he was visibly angry.

Today I got my job offer letter which clearly mentions he is my immediate reporting manager.

Ex is my reporting manager?
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