Re: Black Magic.
Peace teelobhain
Actually there are cases when men marry women out of attraction and then realise that there is no depth to the marriage. Sometimes men want more out of the marriage, such as to be treated with respect that some women stop doing after some time in marriage because the formality ends, other men want to develop their relationships and the women may want to develop their relationship in a different direction. It can be that he chose his friend because he realised that he may have more in common with her. That later on compatibility was more important to him than looks.
You know there are a whole array of possible reasons that do not include black magic. I would suggest that you ask the man why and he may give you a reasonable answer.
One tell tale sign of enchantment i.e. black magic would be that a person stops thinking or is unable to think rationally. This is brought out of extreme mental confusions which can occur from various agents and influences.