I have had a live in monogamous bf for several years now (MonoVCPG) and recently he allowed his heart to wander. He had promised me over and over again that he never would and that he would only ever look to me for his needs to be met. It was alarming and devastating for me when that promise was broken. You can follow in my blog what happened (march 2012 on).
Monogamous promises of commitment are very different and I wonder if your partner sees you as primary because he believes you to be monogamous. I might of missed it, but have you talked with him about your ponderings of dating? And your questions about whether poly is a good choice for you or not?
As a whole I agree with those here that suggest that you make friends and see what happens. The positive part of Mono opening his heart to the possibility of poly love was that he understands me enough now to find a comfortable spot within our lives together. He had some very strict boundaries before he crushed out on his friend and those have all lapsed to a place where I can reasonably fulfill his requests. What I am struggling with is trusting him that he means what he says when he says he wants to stay monogamous. I don't think I will ever trust him or likely anyone else if they ever make that promise again.
Btw MonoVCPG has written a lot on these forums in the past on "mono/poly" relationships. If you do a tag search you will find his posts and other fantastic writings.
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