LW, the guy is cheating on you. He is projecting his guilt onto you.
If he's out of town playing baseball, he's almost surely messing around. That's what baseball players do. The girls he sleeps with are called "road beef."
I think the husband can and will be helpful. Not reaching out to the husband -- not insisting that he listen carefully -- is like being on a sinking boat and refusing to use the life raft. "Oh, I don't want to bother the life raft." "Oh, the life raft probably won't work, anyway." Use the life raft; talk with the husband.
And heed Polly's words about telling the husband that tears are a sign of success. We husbands are programmed to regard our wives' tears as a problem to be solved. We need to be told when the tears are not the problem, but part of the solution.
Would it be too dramatic to say "Anyone who talks shit about Alice Munro is dead to me?"
That doesn't sound too dramatic. It's sensible.
I expected to be amused and instead I was moved. What a pleasant surprise.