I don't know if the pregnancy will "buy sympathy." In my experience, most people are plenty sympathetic when they learn of an infidelity. I told few--but was shocked at how many, among those I told, had been cheated on. They understood.
It's not about judgment. It really isn't. You may have been judgmental in the past---but if you'd had a dear friend who was cheated on and witnessed her devastation, I don't think your response would have been what you described. You might have had a blanket, "Women whose husbands cheat don't take care of their men!" stance prior, but you would surely have thought--given real-life experience, that your friend had been grievously and very unfairly harmed by a man who betrayed her love. You are apt to encounter this when you tell people.
In reality, though, your hardships just won't have lasting impact on most other people--even those close to you. I noticed this during the times my mother and brother were dying, and later during the fallout of infidelity. I remember sitting at an intersection with my sister the day my brother died, and saying, "All of these people around us are living their lives--they have no idea that P is going to die today. Our lives are falling apart, and everything else in the world is continuing like it's normal." People do care--but they have lives of their own. The world DOES continue to revolve on its axis, and the lives of others march on, unhindered---as they should.
So they murmur their I'm sorries---and then go on with their lives because, really, it's like ANY hardship another person experiences: external to them. They have their own struggles--some big, some small. But struggle is universal.
You will likely learn, when you tell people, that some who have been in your shoes, people who really understand. Some may check in on you often--as they might after a death--to support you. I had a friend who surprised me by doing this for ....well, she's STILL doing it, 4 years after the fact! When she hasn't seen me for a while, she makes sure I'm okay and thinks up something for us to do, finds something for me to be involved in. (I don't need this now--really, she'll suggest getting coffee at this point, but for a while, she was helping ensure my connection with the rest of the world by very subtly engineering my participation in committees, social action groups I feel strongly about, etc. She is BRILLIANT, and I love her for this.)
But by and large, it's like death--only with no real social customs to back it up. People will be sad for you. But there will be no casseroles delivered, no prescribed period of mourning.
Others' lives will go on as normal.
And no, they won't be judging YOU. You did nothing. Your husband did.
(It saddens me that this is your concern. I do understand the fear of telling others--but not for this reason; I was scared because it was the kind of news that, once delivered, is OUT THERE. The judgment I feared was whether people would think I was nuts if I decided to reconcile. And even that, I learned, was misguided. People, to be honest, are so wrapped up in their lives that they just don't care NEARLY as much about what ours are like as we think they do.)
[This message edited by solus sto at 7:49 AM, October 22nd (Tuesday)]