6 years ... 2 years dating and 4 years married. Since the divorce I haven't been quite as good, but I'm trying. ;)

Find someone worthy first.

Couple days shy of a year. My first, my last and my only monogamous relationship. I was 20 when it started and 21 when it finished.

Surely I can do better than this?

I was monogomous for all of the eight years I was married...can't say that much for her though. So don't know if that counts towards answering the definition of a monogomous relationship.

14 years for me!

I'm with scarecrow. Been with someone for 9 years, mostly monogamous...but not totally. Open for us both.

20 days shy of 30yrs. when Murphy and I first met in person last June.

3 years for me so far and I just got married so looking at many many more years to come :)

10 years here

Wow! 18 years serially, 11 of which is with my wife.