Wife’s best friend
In life, we can’t like everyone, there are so many different personalities that it wouldn’t be a reasonable expectation. If the person that you don’t really get on with is your partner’s best friend then you can’t really avoid them, you just have to try and get on.
At least this husband made the effort to improve things, in going out for dinner with the friend. I can understand his annoyance at someone not tipping, but I possibly would have swallowed my objection for long enough for the two of them to mend bridges.