As this is a comunicable disease, she definitely should inform her husband so he can see his own physician. The confrontation, if any, can wait.
But she's gotten conflicting information from two doctors. I'd get a third opinion before I accused him of infidelity. As "pjwrites" on another thread pointed out:
"In general practice and in gynecology, vaginal trichomoniasis is a frequent and troublesome problem. However, the trichomonas vaginalis organism is frequently found in an apparently healthy vagina, indicating that symptoms, recurrences, or exacerbations may depend on local changes in secretions, probably due in part to emotional stress. Therapy must, therefore, include not only the topical use of an effective trichomonacidal drug, but also sympathetic and considerate listening by the physician."
I don't know anything about this disease but this excerpt would indicate it can lie dormant for years and not be eradicated the first time. It could be triggered by the "emotional stress" of traveling abroad. And I'm troubled by phrases like "it's practically impossible to get it any way other than sexual intercourse." That leaves some margin for error. Does it seem odd to anyone other than me that they keep getting the same type of STD every time they go abroad? Is he visiting the same gal at the same resort they go to each vacation? Is it a regular squeeze? Maybe he has a girlfriend on the side? Are there more troubles here than the LW wants to face? Can I more wildly speculate? or add any more question marks???
Quick digression (my apologies): PhysicsGirl, I want to take this opportunity to tell you how touched I was by your post the other week when you said someone "was being mean." It was so heartfelt, so tender, so human of you, it nearly brought tears to my eyes. It was like seeing Mr. Spock hug a fluffy kitten. Bless you darling. I don't care if you got male or female parts, or both, you're my favorite 'droid.