I think that what you posted on your first thread is probably true: your H isn't over the A with OW. I take it he still works with her? So he can't really avoid seeing her, and may have reconnected.
It's just a guess, but renewed interest would account for his actions, and makes a lot better sense than an overwhelming sense of guilt. I would not even mention it, since it is painful, but I thought that you may have thought of this, too.
It's so much easier said than done: but give him space, give him time. Try not to question him. Don't express any interest in OW (or ex-OW) at all. Try not to talk feelings or relationship issues. Be kind, be brief, and be busy. Check out Divorce Remedy, if you haven't already.
If you're tired of this, then why not take a break from it? Do something YOU want to do. When he goes out, why not go out with a friend? I think you'll have better luck NOT working on your marriage than by working on it. You love him, but you'll be all right without him. Make your actions speak that message, if you can.
It's scary to hand someone complete freedom, then go cheerfully about your business. But it could work.
