Hi there. Firstly, it does not appear you have any STD
. What you need to do asap is to visit a gynecologist & get a detailed examination done on your wife for any Gynecological infections etc. (more for completion sake & to reassure her). Then you need to approach a marriage counsellor or someone qualified in sex education who i am sure your gynecologist will be happy to point out. It does appear the problem is more deep rooted & more psychological & it will take both partners to be gentle & get to the root of the matter. Talk to her & it will work out. Wish you good health & a happy married life. Cheers!