Let's remember one thing, love is love, sex is sex, sex is not love, you need to ask yourself first if you feel comfortable with her cheating on you, then you need to ask yourself if you can accept that sex is sex.
There are women who need this adventure, to rekindle the fire inside them, we men hardly ever get bored of sex to the point of not being able to cum, we manage to cum for anything, some women don't, and that's why some cheat, because they think their husband doesn't will understand that, others cheat because that's her fetish.
You need to think about all this and then ask your wife if she loves you.
Love is the main thing, if she loves you, I, I speak for myself, would accept it!