So he left her after they got pulled over. The officer said he told McNair he could go talk to her, but he choose not to.
Yes, they were both intoxicated, but I believe when you are drunk, it kind of shows your true self, because you have no inhibitions.
Then after he bailed her out, she went to buy the gun. Perhaps, while she was in the squad car or at Police station, she had her Um huh moment and realized their "relationship" was not as she thought and couldn't handle it.
I believe his wife knew, women have a sixth sense and it is up to us to choose to listen to it.
I truly feel sorry for his sons. He didn't deserve to die that way. But he should have been home with his kids instead of playing like he was single.