ureaplasma positive, partner negative

I have been told that I am positive for ureaplasma.  I have been with my partner for over 12 years and he was tested and is negative.  How can this be?  

[kdaily]

This is not an STD... here is a link for more info.

http://emedicine.medscape.com/article/231470-overview

Also here is an Experts response about ureaplasma

http://www.medhelp.org/posts/STDs/Ureaplasma/show/245287

Let us know if you have any other questions

[Vance2335]

This does not mean that it was sexually transmitted. You can get it a couple of different ways and just because you have it does not mean you pass it.
Your partner either had a false negative, you had a fasle positive (both rare), partner got it, gave it to you, but took medication to clear it up or you got it and never passed it on.