It could simply be your cervix. In some women, it is not neatly at the end of the vagina, it comes in at the left, or it hangs into the vagina a little farther rather than just being at the end. Double uteruses are pretty rare, but being able to feel the cervix is not so rare. I would, however, go see an ob-gyn when you can, for a regular checkup, since you're having sex. Then you could ask what they see in the pelvic exam.
Hi Barb
I have two cervix's and a uterus with a wall down the middle... strange I know and there arent that many of us that have that. Its hard to find any information on it. With my double cervix i have this issue when it comes to intercourse. You can always find out when you go for your pap test your doctor would be able to see it if she or he looked or check with your doctor and see if you can see a specialist about it.
If you want more info let me know and I can go more in depth about it.