Eric - is the OM married? One thing you can do is to expose the affair to OM's wife. Affair is a fantasy, when you expose it may bring it to an end.
And if you can, stay in your marital bed. I know, extremely hard under the circumstances. If you leave your bed or the bedroom, she will turn it against you one way or other. Let her leave if she wants to.
M53 H54 D17 M33Y T38Y Bomb OW 09/09 OUT 10/09 BACK 11/09 OUT 01/10 WANTS TO R 04/10 BACK with OW 05/10 Wants to Reconcile 05/11 I said NO