Can a man be sealed to more than one living woman?

A tbm man who I am acquainted with got a divorce a few years back. He and his first wife were sealed in the temple. Now he is re-marrying. And being sealed to the second woman in the temple.

Just wondering how this works. Does he have to undo the first sealing? First wife (now ex-wife) is alive and well. Can a man be sealed to more than one living woman?

I know that when a man is widowed he can be sealed to another woman. But not sure how it works with divorce. Also if a sealing is undone, where does this leave children who were BIC?

I am aware that the whole thing is made up and only matters to people who believe it matters. But I'm curious about how they think this works.