Why It’s Good If He’s Friends With His Ex Wife
They have shared family
At one point, he was her family’s family. He was her parent’s son-in-law and her siblings’ brother-in-law. He probably formed deep bonds with those individuals. To some extent, he will (or should) always have a love for those individuals who treated him like family. So he may be friends with his ex because he’s still friends with her family, and that just shows loyalty.