Hello and welcome to HCM. Thank you for your query. I am deeply sorry about the news you very informed about your husband, but sadly the presence of a greenish discharge does relate to a sexually transmitted infection. Yes, most commonly trichomoniasis, and it should have been detectable by now, but there can be exceptions. The use of Dalacin can cause a change in bodily functions, and thus slightly suppressing your immune system, that could result in the presentation only while on the medication. As you have already mentioned being tested by all the above mentioned diseases, it is not right to ask you to get screened for all sexually transmitted infections, but my best advise right now would be to get the vaginal discharge tested in the laboratory when it does appear, and also report to the laboratory for a vaginal swab, that will help in microscopic analysis of the cells, which should help in a confirmation. Regarding your husband, there are many infections that have differing incubation periods, like for example, with simple tests HIV can return a positive result only 3-6 months after contact with a HIV-positive individual. So, it could be possible that the infection that you have could be in the incubation period or is latent. I would recommend you to report to a doctor as soon as this appears, and get elaborately examined as this should hopefully help. Wishing you lots of luck, and hoping this is nothing serious. I hope I have succeeded in providing the information you were looking for. Please feel free to write back to me for any further clarifications at: http://doctor.healthcaremagic.com/doctors/dr-shoaib-khan/64581 . I would gladly help you. Best wishes.