Say yes only if every account you'd report is jointly owned with your spouse, your spouse files a timely FBAR covering them all, and you both sign FinCEN Form 114a (which you keep, not submit). Then you don't file your own FBAR. If you also hold any account separately or by signature authority, you file your own.
The FBAR asks for a reason when it is filed late. Pick the closest to your situation; it is printed on your worksheet so you can select the matching reason on the form.
The form asks for a short explanation when you choose Other.