nah but the way you said it relates more to that than to what you're saying now
and Sagisō doesn't have grand ideals per see. Her entire motivation is just doing what she wants, and right now she wants to find a husband. After that is achieved she'll flirt around a bit and then ditch him for like...a year or so. She's quite the fickle girl.
Alright, let's take a look at what I said in that context.
I'd said she was one to do whatever she wanted, and that after achieving her current goal (Finding a husband) she'd leave him. In this context, I'm talking about physically leaving, as in she wouldn't be within his vicinity. Note that I gave a time-frame and that means that she'd return after said time-frame.
She's a free-spirited girl, so she'd naturally want to pursue her own goals.
If her spouse were to insist on chaining her to him, then that brings into question his quality as a spouse.
just someone that stays with their spouse
Proximity does not make a loyal spouse.
You can live with your spouse and be unloyal. Loyalty, as I would call it in this case, refers to how she treats others in relation to her spouse.
As far as Sagisō is concerned, once she finds her spouse, all of her romantic affection will belong to him to do with as he pleases so long as he doesn't do anything that's quite obviously going to shatter that trust in him.