You've received some great advice here already regarding opening your marriage and managing your feelings. My concern is a little different. It sounds as though you and your wife have had a difficult year.
It's possible your wife's desire to be with other men has caused the problems in your marriage, but it is also possible that it has not. Are you so focused on this information that you are overlooking other issues? Think back to when you and your wife were at your roughest patch in the last year. Did your wife talk about being unhappy with finances, inlaws, family status, loneliness or something else? Were her concerns addressed and resolved? Were your concerns addressed and resolved? Or are these other issues just in the background now?
Since your wife is willing to wait awhile, I might put some energy into resolving preexisting issues rather than focusing completely on this one. Even if you both decide that non monogamy sounds wonderful and perfect for you as individuals and as a couple, there will be rough spots in the beginning. Working through other issues as a couple will strengthen your relationship, give you a greater sense of security and restore trust, making the transition easier.
If you think other issues are causing significant dissatisfaction in your relationship, I'd tell your wife you don't want to lose focus on those things, that you want to try to work on these things while you learn about and consider opening your marriage. If you think opening the marriage is the only serious conflict between you, please disregard this message.