I'll read the rest of the thread after I post... I'm so impatient!
I know there are a lot of debates about the use of primary and secondary, different people have different ideas about what works for them. These terms have always worked well for me, as long as you throw in "could be a co-primary at some point" at least.
I assume my boyfriend of half a year considers me a secondary partner or equivalent, it's not as if we sit around discussing labels (and I don't think I want to let it matter one way or another). He is married and has another long term relationship. I am OK with feeling and knowing that I am not a primary, as I would not, could not, shouldn't want to be primary to him - as it'd makes no sense at all.
A good thing about dating people vastly different from you/a current partner, is that you can enjoy the good things without feeling sad about what you don't have. The bf is far too autonomous for me to have as a primary partner. If my husband wanted that level of independence and privacy, I never would've married him, and sure wouldn't want to do poly with him. This doesn't stop me from thinking what I have going with my boyfriend is an awesome relationship with lots of good things about it. And if it ends up being a relationship that lasts another month or another 20 years, I am pretty sure I'm comfortable with it being secondary.
This is mainly because nobody is trying to make me feel less than - which is probably what would trigger me to feeling the idea of "secondary" was a bad thing. On the one hand, my bf's wife does not have veto power - though if she did decide she wanted our relationship to end, I don't know what would happen in his head. I thought about asking him this, but truth is...it doesn't matter. Knowing wouldn't be a positive. If she wanted me gone, I think I'd be gone, because I can't see not bringing good things to my relationships, including those of my metamours. It isn't an easy situation for her though, so ya, there's some stress where I'd really prefer rainbows and kittens. I also think we are never going to all spend together and that isn't ideal for me, but I also have the benefit of not spending enough time with him for us to have a fight, or drive each other crazy, and that's nice too!
I tend to want to date people who are married so it does not seem to be an issue for me - but if I was single, or dated single people, I am guessing it could be more of a bone of contention, comparing me to their other partners, in the amount of time, love, commitment I feel. Nevertheless, as it stands, I just focus on what is good, and enjoy what there is.
Happiness will never come to those who fail to appreciate what they already have.