I just riffed off some stuff that the FB, the ex- wrote in an email to me about relationships and dating, and I think it actually turned out fairly well. It includes a few details relevant to the dating history he and I had, but isn't particularly revealing or personal, so I'm leaving them in. It was also written government email account to government email account, so there's a lack of my usual tongue-in-cheek sauciness. ;) So, in a few rambling paragraphs, here is the nutshell version of my thoughts on relationships and dating:

I'm not sure it matters how people in general define relationships; it's how you and the person you're seeing define what you have going on. There are so many different grey areas in dating, which I know you hate, but it's a fact of life. What matters is the understanding that you two have, and where the boundaries for each of you are drawn; if that involves other people, so be it. If it doesn't, well, that has to be spelled out and acknowledged at some point. However, as I said to you when we were dating, though I understood where you were coming from with not wanting to kiss me if you knew I might be kissing someone else, it's also extremely unrealistic to have that sort of expectation so early on in a dating relationship. Unless it's otherwise stated, or until the lines are drawn, if I'm just dating someone, I assume they're seeing other people and I feel at liberty to do the same. It doesn't have to be talked about, and in fact can make for uncomfortable conversation if it does come up, but unless the physical or emotional progression dictates boundary-drawing time, it's all free.

As for whether one person can fill all the expectations... it's a priority system of sorts. You said before what your priorities/requirements were, though I don't entirely remember them all, barring the caucasian point and possibly wanting children, and if those are important to you, then they stay on the list. But you negotiate with yourself as you date and meet new people; once upon a time, I might've preferred to date someone who made more money than me (back in the days when I made under the poverty line) or whatever; now I don't care, provided he's working someone stable, sustainable and enjoys what he's doing, and it's above minimum wage. But that also factors into me liking guys who are intelligent and have at least a partial drive; few of those are still working McJobs at my age.

Ultimately, if you're not satisfied with the person you're dating, that's going to reflect in your interactions with them, and will cause problems. If someone is lacking in something that's important to you, then you have to either address it or move on. If you're able to compromise or can recognize that the fact that they're blonde instead of brunette (for example) really isn't that big of a deal, then... *shrug* You stand a chance.