Well, you can't have a divorce based on adultery which did not take place during the marriage or, at least, you cannot petition for divorce based on adultery in those circumstances.
If the marriage has broken down beyond repair then you would be wise to seek a divorce sooner rather than later. You can almost certainly issue a divorce petition now based on unreasonable behaviour which most people can. It is by far the most common ground of divorce precisely because it does not involve waiting.
It would almost certainly be very unwise to wait until you have been separated for two years before seeking a divorce. After all, if your ex is happy to make you wait now what makes you think that will not still be the case when the two years are up? When push comes to shove the consent required for that ground for divorce might not actually be forthcoming. Why take the risk? And, of course, what do you think would happen if you won the lottery or inherited money between now and then?