It does matter if she used condoms. Condoms offer a lot of protection, if not total protection for some stds if the condom remains intact.
Keep in mind that this thread is an old one, and she might not be around to read your response.
Aj
Condoms aren't 100% so it doesn't matter if you used condoms or not.You need to find out if your boyfriend has the same thing because he may be the one to give it to you.
Have you never had unprotected sex?
And doxy isn't a good treatment for vaginitis - did they tell you the cause of it? How did they test you for that? If they tested you for vaginitis the first time, they would have found the trich. Doxy is the med for chlamydia, so I wonder if they were treating you for that. I think you need to find out what they tested you for, and what they didn't.
The doxy probably gave you the yeast infection, but it wouldn't cause trich.
Has your man been treated for anything?
Aj