I would make an appointment with a marriage counselor, invite him, and go. If he doesn't want to go or gossips about it to his friend, he isn't taking the marriage and your feelings seriously. You should go talk to the marriage counselor anyway even if he doesn't. It could be his wake up call to take your feelings seriously.

The only thing you have to lose by talking to a marriage counselor is the dynamic in your marriage that isn't working. I wouldn't give an ultimatum unless you are prepared to act on the "or else" part. Being dramatic and going big only works in the movies. Real life is much less predictable.

I hope things improve for you.