Lost count of how many times this was said? He cheated because he wanted to, he lied because he could and he's only sorry because he got caught. Why will this time be different? Because you prayed about it? Didn't you do that last time? And the time before that? Will you do that next time too? Be careful of the example you set.
It pretty much always does. The only thing I have learned in my life is people dont change. B will always be a scumbag liar and a douchebag cheater.