Yes, I would encourage her; even tease her a bit with how other men look at her and lust after her. Maybe even a bit of roleplay in the bedroom around her being with other men (a pop star, film star, neighbour, work colleage, etc.)
There is a lot of fantasy but the reality is different. I suggest thinking about things before you go through with it - a pros and cons list. Good luck and let us know what you and your wife decide.
She needs to get rid of that black bush and show us her pussy hole better. That way when a big black dick is fucking her the stud can see how much he is stretching her!