Have you spoken to her about your fantasy? Have either of you spoken at all about any of your fantasies? Have you considered what you'd do if she refuses to sleep with another man? Have you considered whether she might like this new lover more than you and kick you to the curb?
Since you've posted this on an interracial website I'm assuming you want her to have sex with a black man. Do you know what her feelings are about interracial relationships? Would she even be open to that idea? And if not would you be OK with her sleeping with a white guy?
People on here are going to give you all sorts of advice about showing her interracial porn and cuckold porn; they'll advise you to buy a big black dildo to play with. But without communication- without actually having honest conversations between the 2 of you this is a disaster waiting to happen.
Ultimately it's not your decision whether you're going to "share" her or not. It's her decision whether she wants to indulge you in this fantasy of yours.
Talk to her!!!!!!!!!
