So Glass's WIFE was in on it the whole time?!?

No. She was dead the whole time. That wasn't really her at the end. She was just an illusion out of Glass' troubled mind and for that matter, some of his bizarre dreams. And even though the ending is left up to interpretation, I took it as a symbolism of him somehow managing to get some closure after all he's been through and decided to let his wife go. Her walking away is due to him deciding to let go of the past and move on with his life. And the look on her face looks like a "farewell" look.

He had some closure over his son in the church dream sequence but not so his wife at that time. When Fitzgerald told him that revenge won't bring his son back, perhaps something in his mind finally processed that nothing he could do can bring his family back. So, he had no other choice but to let go of his traumatic past and let his wife go.

The name of the movie is the Revanent, and a revanent is just an animated ghost,therefore that's what I saw his wife as for the movie. She was the original driving factor and once his son died his whole family was.

Lol...

@SWLinPHX-2 Hey, that's marriage.

I think the OP is a veiled reference to The Edge.

That wasnt his wife - that was Powaqa ??