I would have told her that you will be proud and happy to be there to support her. However you are her husband and that you don't feel it's right to be in the house of God with her affair partner.

Straight forward and direct. I think you should still go. If at the very least to show the OM that you aren't afraid of him. I think if you avoid it, it'll seem weak.

M-43 W-40
2D - 9 and 5

Emotion, yet peace.
Ignorance, yet knowledge.
Passion, yet serenity.
Chaos, yet harmony.
Death, yet a new life.

RECONCILED AND WISER