Welcome complicated: I'm sorry about the difficulties you have had with your marriage and with the situation with your co-worker. Sometime mid-life crises happen and we just need to put it behind us. There was close to a 30 year age difference. The harsh reality is that although it must be flattering to have a relationship with a beautiful, much younger woman, generally something isn't healthy about the relationship. You can't fix her.
I reconciled with my wife and moved back, but now I guess I deserve my fate in that I'm stuck in the same building as my ex-lover... .we are in opposite ends of the building, but it is difficult to avoid her altogether as we only have perhaps 20 on staff... .looking for other ways for no contact when we work in the same place. I am open to suggestions.
I've had a few uncomfortable situations with people in the workplace. I eventually learned my lesson to not get involved with someone I worked too closely with.
What's behind your discomfort? Are you embarrassed? If she would be interested, would you resume a relationship with her - perhaps leave your wife again? (you are on the Conflicted or Deciding Board).
If you haven't seen her face-to-face, since the breakup, then the first encounter could be awkward. Is it possible to just say hi, be pleasant and brief. If you can avoid working with her on any assignments, that would be best. What are some of the possible situations, that might make contact probable (lunch, breaks, teacher's lounge?)