While I'm away, readers give the advice.
On telling people their mates are being unfaithful:
Having been there myself, I think people should remember that telling the truth does not always make one popular or even appreciated. Consciously or unconsciously, those who do tell the truth may be motivated by a bit of a "savior" complex ("I'm going to save my brother from a lifetime of deceit and misery") and may expect to be loved or seen as heroic for their efforts.
Well, they don't usually make whistle-blowers president of the companies they expose; the outcome is usually ostracism and anger when the truth costs thousands of innocent people their jobs. Not a rationale for not doing the right thing, but simply a caution: Your truth exposes one person as a cheater and causes the other great embarrassment. It may give them a better grasp on reality, but doesn't make them happier.
For my part, I've decided to trust my adult friends to make their own decisions, good or bad, and be there for them when things fall apart. In can be painful to watch these train wrecks in motion, but it is free of the overt judgments that breed resentment, and has strengthened more long-term relationships than I can count.
On facing the awful stay-or-go decision:
Get yourself ready to get back into the single world. Chances are you could use a little "sprucing up," whether it's dieting or improving your wardrobe. Exercise is a must either way.
If you do get divorced, you are going to have to do this anyway, so you might as well get a head start. It will also serve the purpose of possibly rekindling your spouse's interest in you. Stop nagging and start living your post-marriage life.
After that, start socializing. Make plans for both of you but have an option if s/he wants to stay home. After a couple of rejections you can give a blanket statement saying you are only going to plan for yourself from now on unless you hear otherwise. Be as cheerful as possible, as if you are glad to have time to yourself. Go out with friends.
If there is still no progress, start working on your finances and getting the rest of your life in order to make any potential split as efficient as possible. Get advice from friends about divorce attorneys. Start researching where you or your spouse will live after the divorce. S/he will see you are serious and it will be much easier for you to make a difficult choice.
On announcing a pregnancy to a friend who is struggling to get pregnant:
I was that friend, or a version of it, at one point.
My husband and I started trying to conceive right after our marriage, but it took four years and lots of medical intervention to do so. During that time, many, many of our friends did get pregnant. The most thoughtful friend of all wrote me a very nice card telling me she was pregnant, because she thought I would want time to process the information privately.
I still have that card . . . and a charming 7-year-old who is thankfully still sleeping on this rainy Sunday morning.