Her yes doesn't mean she will jump straight into it. She will go back n forth on this but eventually she will become a hot wife. Just make sure you tell her you enjoy seeing her that way you need to convince her that your interest lies only in her pleasure
Without some prior understanding or foundation, I don't see how denigrating yourself, making her think you believe she sees you as somehow deficient or inadequate and herself in heat for strange dick -- in short SHE wants it, therefore you want it, and THAT's the impetus for this -- is a thing that would excite or motivate a normal person to even contemplate exploring this way. Gotta believe the negativity inherent in it would go over like a lead balloon. You're talking about a spouse. A partner. A lover. A friend. I find it bizarre that someone would imagine that might be the way to broach the topic/pique her interest in this.
She'll have to know you've thought about it, do think about it, and that it's something that seriously turns you on, an adventure you imagine trying together if she too would ever want to. You have to be able to talk to her about why that is, why it moves you so.....from a positive standpoint. You need to encourage her to be open with her fantasies too. And not just in playtime. Re trying something with another man, she has to hear you say you want it, digest it, wrap her head around it, become comfortable with your desires. To accept and realize it's something quite real on your end. That you think it would be rewarding and good; hot and sexy and exciting and fun. And that IF you ever tried it the two of you would still be rock solid regardless of how it goes. She might play at your fantasy but isnt likely to embrace more than a fantasy unless she trusts you and believes that. She'll need to accept all these things about you to ever accept herself wanting or being willing to try them too, to give herself permission to. Even then, you'll need to realize that almost certainly she'll be doing it for you, because you wanted it.
I have to believe that relatively
very few men who'd like to see their wives with other men are also thinking about sex with other women, or playing that angle at all. Also believe a wife will probably know this instinctively, if husbands are able to communicate these kinds of desires, and the sometimes conflicted emotions and doubts connected with them. Most wives will realize they have next to nothing to fear in that regard. That certainly doesn't mean there wouldn't be myriad fears, concerns, considerations, and obstacles of other sorts, both philosophical and practical, if she's even willing to entertain the notion.
But I do think a wife who is open and communicative in dealing with a spouse who expresses these things will understand that SHE has the capacity to satisfy her husband completely, fully inspires and occupies his lustful desires, and that what he's looking for -- at least sometimes -- is something new and different sexually, but always with her at the center of it, driving discovery for both of them. She'll "get" that in her own desires she holds the key to
any kind of change in their sexual bond and that THAT is really a secondary thing anyhow, made possible only by what he really wants above all.....that she love and accept him at greater levels of intimacy and vulnerability, with deeper understanding of each other. That's the type of bond that grows stronger and can make all kinds of things -- including cuckoldry -- possible in a marriage.