I think I get it (Ben speaking here). I told K when we were together that Bex was my first covenant and nothing she and I had would ever supercede or replace it. At best, I could offer her equal status. And that meant that if Bex said, "I need you" then I would be there for her.
I have a 20 year history with Bex that can't simply be equalled in a few months or even a year--and anyone who would think that it could really can't understand the depth of my love and committment to my beautiful bride.
All that being said, if I was with Bex and my new covenant bride came to me and said, "I need you"--then I would also be there for her. And Bex would understand.