Did you get stiched after???? Also how long has it been since this happened?
While stds are always a possibility the above factors will matter in regards to how accurate someone can respond to you, because if it has been long enough for it to start healing then it is a good chance that it may also be a cause of the itch.
Some sexually transmitted diseases, yeast infections, bacterial infections, sweat and poor hygiene can result in an itchy vagina. IMO ur tearing is from ur partner being a little too rough. I've personally never heard of "tearing" during intercourse resulting in an itchy vagina. Try an over the counter "anti itch" cream. If that doesn't work, make an appt with ur DR just to rule out all std's. Good luck!
im talking about my vagina xD
go see a doctor that specialize in the anus.