Leaving such a lovely wife alone, and moreover at my sister's wedding with many guests, is reckless. The sense of celebration, alcohol, and temptation would do the trick. The negro noticed the bored girl and was rewarded for his attention and concern for the beautiful stranger. She thanked him like the female the male had chosen for the day. Now her body will remember this unforgettable encounter.
Well, if they're friends, they're allowed! What if she needs help in the future, or will be bored - they can always pull. The main thing is for her boyfriend to enjoy it.