GFT, I think you and I have different definitions of "important" here. You're looking at it as "Andy is more important than anyone else because he's my husband and we live together and have entangled lives." I look at it as "Hubby has more of a share in my life because we live together and he's my husband and we have entangled lives, but as far as how I *feel*, he and Woody are equally important. I love both of them deeply. I would never be able to choose one over the other. The *reasons* for their importance are different, but the *level* of importance is the same.
We may mean different things when we say "important". I'm using it as a proxy for "could I give this up? how much would I lose by giving this up?"
And the truth is, I would grieve - deeply - if Dag disappeared from my life, but I would be ok. I have Andy and my friends for emotional support, and an okc account if I need kinky sex

If Andy was gone... God, I would never be completely the same again. I don't know if I could ever find anything that fulfills me the way my relationship with him does. He meets so many vital needs in my life that no one else does. Possibly no one else could.
So could I choose Andy over Dag? Yes, I could. I would, if I had to. If for whatever reason I just could not sustain both relationships without going insane. And fwiw, I would expect - and hope! - that Dag would choose his marriage and stable family life over our relationship, if it came to that.
The weird thing is, it's not "veto power". If Andy actually told me to stop seeing Dag, I'd a) get him checked for a brain tumor and b) drag his ass to counseling because that is NOT how we work. Both while continuing to date Dag. I'm thinking more of what I would do if I just didn't have just the emotional bandwidth for two relationships. So I wouldn't choose Andy, exactly. I would choose *me*, and that would mean choosing the relationship that I need more.
Actual conversation from a few nights ago...
Me: We don't have veto power ...
Andy : I vetoed Tyler [asshole narcissist I dated for waaaay too long]
Me-: No, you said it made you unhappy that I was still dating him, because I cried every time he sent me an email detailing all the ways I was screwing up my life.
Andy: Yeah...
Me: You didn't tell me I had to stop seeing him.
Andy: Well, of course not, you're an adult.
Me: What would you have done if I hadn't stopped seeing him?
Andy: Talked it out. Maybe gone to counseling. Maybe said I couldn't be your comfort person when he hurt you, because it upset me too much. Maybe eventually told you I couldn't stay in a relationship with someone who would set herself up to be hurt over and over by a narcissistic asshole.
Me: Veto is like, Stop seeing him! End of discussion!
Andy: Who the hell stays in a relationship with someone who would say that?
I really do love my husband <3