Hey Cherry, you've held back for such a long time so one little text message calling him out on the OW won't hurt in the scheme of things.
You say that you don't know what life will be like without him but can you honestly say that he has been taking an active role in your marriage for the last few months? From what I gather he has hardly been there in spirit let alone body so I think your going to do just fine. I think the question I would be asking is how is he going to cope with out you!
Me - 47 H - 45 D-16 M - 6 years Separated - May 16
Don't leave me behind can't you see me I'm shining... (Years & Years - 'Shine')