How did it end?

Hmmm. I thought he walked back into that town after being dropped off by the sheriff. He did not want to look "weak" by driving in by car. He did state that he wanted to "walk in from the desert".

In the first of the movie, after being left out there he screams " I will walk out of here, I will walk out of here and I will see you and his face ".

I just watched this film again, and I think the OP is correct: Richard Damian turned to his right and walked into the desert. He definitely wasn't walking on the pavement of the highway that he was standing on earlier. I think think the 360 degree camera pan was meant to tell us that his entire personality had completely changed and that he had just realized that his life had far more meaning living 100% in nature than surrounded by wealth and artificial trappings. It wasn't made perfectly clear, and I think he would be stupid to re-enter the desert with a broken leg, but I think that's what the film was trying to tell us. He also told the sheriff to let his wife and her lover go. He really just didn't care about them anymore at all - good or bad.

He does walk off the road briefly into the desert, but then turns back towards the town. (This would be necessary if he were to "walk in from the desert", as he requested.)

As for his wife -- he tore off her scarf b/c he no longer cared about her, or needed revenge. He had found something more important -- himself. That's also why he told the cops not to pursue them. He realized he was a jerk before, which caused her behavior. He'll probably even give her some money in the divorce.

I did think briefly he was going back into the desert for good, and started laughing, as the idea was so ridiculous (with him seriously injured, and finally liking himself, and being admired by others). And that would make for a plausible 70's-style ridiculous/cheesy ending. But then he turns back toward the town. That wouldn't make sense if the point was to show him staying in nature permanently. (Which he barely survived.)