Do you really think she'll won't tell if you succeed?
with no risk of she tell my wife if seduce failed?
Okay, you really have
not thought this through, have you?
Especially ... "if seduce failed"?
Do you really think it matters whether she will tell or not if she sleeps with you?
Even if she sleeps with you multiple times, and she doesn't tell while you do, don't you think at some point she will tell?
Even if afterwards?
I'm sorry to pick on you, but this is what cracks me up about my fellow gentlemen.
It seems like we can only see to the point where we get laid, but not afterwards.
That's why men cheat, get away with it, then are overridden with guilt later and openly confess because of it!
Denied, no answer, etc... whatever, we see that.
But we assume all is good and happy if we succeed in getting laid.
And there's no problems after that, right?
If you married a woman who does not share the values of having a polygamous relationship -- guess what? -- you now agreed to the same values!
If you don't want to, consider being honest with her about your desires.
If you fear divorce for even asking, then maybe -- just maybe -- you should reconsider why you are married to her.
Honesty is the ultimate foundation of any marriage, and don't stay married just to be married.
At the same time, consider the "value" of the marriage itself, and what "sacrifice" you are going to make by not giving into your desire in comparison to the one you will.
That's what marriage is about, not what other people say is "right" or "wrong."
It's about sharing values (not "fixed" or "popular" ones), being honest, telling her what you want and conceding what you don't need, what will only hurt her (regardless if she found out or not).