This is a decision that only you can make. Does your SO know how you're feeling about them? Seeing a marriage counselor can help clarify these feelings that you're having.
If you are not sure about staying with your wife, perhaps you should talk to a counselor first before you lay all this on her and the best way to let her know. Good Luck to You.
"Afterall, everybody only hears what he understands." by Johann Wolfgang von Goethe