Yes, those abc girls are addicting.....just like OM is to your wife...and she let that OM have a relationship with her now, so it is even worse.
You need to make a plan. You are coasting day to day. You either back off until she comes back or divorces you or you give up and just "be friends" in hopes that she realizes she screwed up and comes back. You can't keep flip flopping...well, you can, but it won't help you any.