Male partners of females with BV are not treated so I doubt that you being treated would make any impact and I also don’t believe that Trich would give you these symptoms. You could talk to your doctor about this, yes. There are also other drugs used to treat prostatitis more commonly I believe. If you aren’t better on 3 weeks of doxy, I would ask him about the quinolones which are very often used to treat prostate problems. Trich in men live in little ducts around the urethra, so since you both pee and have sex with your penis, looking in urine for trich is not completely unreasonable.