I'm trying to get my wife interested in having sex with a large cocked black man.
From the posts you've put up, I'd say she's already interested. Often, when a spouse starts screwing outside the marriage, and this happens with both sexes, it elevates their cravings for more sex, which is why they initiate more sex with their spouses after an affair. You're probably a cuckold and don't even know it. She's probably fucking you because she's still aroused after fucking him.
What you're assuming is that
you'll know when she starts having sex with black men. In most cases the wife isn't going to share her affairs with her husband because she's not sure how he's going to react + she doesn't wish to encourage him to have affairs too. But, for now, you'll be the beneficiary of her elevated sex drive. If you insist in knowing for sure, pay more attention to the taste, smell, & feel of her pussy and body, especially when she's been away from you for a few unscheduled hours, and, start checking her soiled panties for cum-stains or an unusually larger number of soiled panties in the washroom.
If I was you, I'd start rehearsing how I'm going to react when the truth come out, because once
she knows that you know of her infidelities, (assuming you don't go unhinged on her), she's going to go into overdrive with fucking black men, and that elevated sex drive of hers that you're enjoying now, will almost assuredly be spent fucking more black me, not you.
Rookies!
Mac