HELP! take 6 months off work (or 3 months & then part-time)

plainandsimple

DH and I have been arguing/debating my maternity leave all evening.  I have a really great career with a very good salary.  I get to take off 3 months paid, and am also allowed to choose to take another 3 months off unpaid.  Ever since we began TTC about 3 years ago, I have been looking forward to my 6-month break from my stressful and all-consuming job to devote it to my baby, knowing I will then go back to work at the end and very possibly continue there for the remainder of my career, with too-little time with my kids.  I am on a slightly reduced schedule right now (which is still amounts to 40 hours a week in my field).

Today I mentioned to DH that some people at work would rather have the new mom take off 4 months, then segue back in at half-time, slowly working back up.  He was very pleased with this and thinks we should consider it.  He says "why do you want to be home for August-January and sit in the winter weather  for the last two months, unable to go do anything fun because you have no income, when you could work part-time during those months and then be on a reduced schedule the following year and have more time in better weather and with an older baby." My reasoning is that I just want a fresh mental break from all things work-related, for as long as they'll give it to me.

The complication is that DH is very, very unhappy in his job and has long wanted to quit and stay home with the kids (we have a preschooler).  He says if we have zero income for 3 months then he'll have to either stay at a job he hates for quite awhile longer (which neither of us want him to do) or go find some random job during the months I'm not earning income, which seems dumb to him when (1) my earning capacity is exponentially higher than his  and (2) he says it's a double standard because if he were the bread-winner and I had a baby, the working husband would never say "hey babe, I'm taking off 6 months and if we can't swing it financially, you'll just have to work part-time for awhile."  I understand his viewpoint.  But I also feel like I am committed to a demanding career for the long haul and if we have to sacrifice (go into temporary debt, delay buying a new house and radically cut back expenses, send him to work some random job for a month, etc.) then it's worth it.  It's a hard argument because although I sacrifice a lot in terms of being a working mother in a very demanding career, he sacrifices a lot in terms of being a supremely supportive spouse (doing all the house cleaning, day care pick-ups, etc., while also working himself).  Also, because DH does all the bills & financials, he is too-keenly aware of the financial impact and I am too blissfully oblivious.

What would you do?  I feel like I want to ask for the full 6 months and then, if it turns out that I'm feeling useless at home with a colicky baby and DH (who can take care of said baby by himself) in the middle of the winter, then I would change my mind and go back a month or two early part-time.  But I fully expect it could also be the most wonderful 6 months of my life with my baby, and would like that option to be kept open.  DH would like a little more certainty than that, since he thinks it affects whether he quits his current job or stays at it (miserably) from now through my maternity leave.  When I tell him to "just quit and be happy," he says we can't afford it.

 Am I being selfish?  Short-sighted?  Is he?  What would you do?