How long is too long?

Sometimes in a marriage, you have to talk to your partner about "serious" topics.  Decisions must be made, options considered, or progress evaluated on things like finances, family schedules, or putting the relationship on the "front burner" now and then.  My guy has told me, though, that his biggest fear in starting these "serious" conversations is that they "will never end." He said while we talk he keeps wondering "Is this almost over?"  Kinda like I feel in the dentist chair?   This astonished me, because we are not a couple who spends a whole evening, or even an hour either talking or arguing about serious topics.  I have even monitored the time in order to better understand his feeling like this... to make sure I wasn't trapping him for hours on end, but not realizing it.  A recent example was checking in to see how our new strategies for tracking the budget are working for us.  (And they are working, so shouldn't this be a "good news" conversation?)  It was 12 minutes long!  And he was edging away as we finished up.    My question to ADHDers is, is 15 minutes really too long to talk about serious stuff?  Or does 15 minutes feel like hours?  I want to clarify that these are not heated, contentious, arguing discussions... I am not nagging, pushing, blaming...these are "two people who love each other" discussions about making sure we schedule an evening out, or celebrate how we're saving money toward an exciting goal, or what changes we might need to make in our morning routine so we both leave the house feeling good.  I'm smiling now, because my guy would read those words and say AAACCCH!  LET ME OUT!  DON'T WANT TO TALK! I think it is physically painful for him to talk about anything other than his current projects, a story from the news, or what the neighbors might be up to.  It's like he wants to avoid confrontation, but there  is no confrontation.  Sometimes the topics are even ones I've heard him suggest, e.g., "We need to talk about what to do about replacing the truck."  It doesn't seem unreasonable to me to say that 15 minutes is not "too long" but am I asking for too much?  Or is he playing me, and any amount of time on topics he'd rather not think about is too much.  He always suggests we do it at another time, and that time never seems to arrive.  I'm not going to stop requiring that these conversations happen -- that's one of my bottom-line needs-- but I had hoped to cause him less pain in the process.