I think that you should tell your H that you do not agree with it, but that he is free to file for divorce if that is what he wants. I told my WW precisely that and it was a relatively quick and easy conversation. She did, however, do just that. Looking back six months now, I don't regret saying it that way at all, nor do I regret telling her to either cut off all contact or move in with OM. Although it is a heck of a sucker punch if they promptly file and move in with OM/OW, you'll get over it more quickly that way and I remain firmly convinced that everything falls apart for a lot of people. On the other hand, if it ends up going well, then there's very little left that you can do about the situation other than move on. Good luck. This will pass and things will get better sooner than you think they will.