Asparagus, I really don't envy you.
That's an awful decision to have to make, and one you shouldn't be asked to do alone.
I have to say think it seems strange (ethically grey maybe?) to go back to work solely to take advantage of a maternity leave. I could never do that to myself. It would stress me out too much. When I work, I give so much of myself to it. I could never fully devote myself if I knew I was just doing it until I was eligible for coverage for another baby. I would feel so phony, and I wouldn't really be able to get into it knowing I would have to give it up. For me there is nothign worse than doing a half-assed job. But I guess you don't see it like that...
Just hypothetically, if the roles were reversed, and there were paternity leave in your country like they have in some Scandinavian countries, would he be willing to do what he is suggesting YOU do? Even if you are sort of on the fence about working, it's still not just a hobby to pick up and drop off like a long novel. It's a career. A woman's career takes just as much (actually no doubt several times as much) work and devotion to maintain and build as a man's does.
Unless it's not really a career per se, and you DO think it is sort of just something to make some cash and pass the time, and you think of being a SAHM as your career, in which case that's perfectly valid and wonderful, too. But in that case, why are you stressing?
Maybe though there could be a compromise. My SIL for example negotiated with her third daughter to have six extra months unpaid leave and since then has arranged to work only four days a week and has negotiated for extra weeks of vacation in the summer to be able to spend more time with her kids in exhange for higher productivity during her working hours. Perhaps your employer would be open to something like that.
Or maybe you could put your degree to work for yourself (no mat leave, of course, but you could make your own hours and all the profit is YOURS). My SIL husband decided to do this so that he could be home more and make his own schedules. He still travels several weeks out of the year, and goes to the office some days of the week, but he can rearrange things to help suit SIL's schedule...they worked TOGETHER to make arrangements where they both sacrificed a little and both changed things, to make it work for them both, so neither felt cheated out of their own future.
I think you might want to talk to your husband about your doubts. It's all well and good to plan a big family, but if you are the one left behind to put your degrees on wall as memories while he galavants around the world fulfilling his work goals, that just doesn't seem fair to me. I am sure he is really happy. I wish I had a wife like you to stay home and look after my kids and my house while I travelled the world for my job. You are very, very sweet and giving and wonderful to help him make that happen. I hope he appreciates you. I know count myself extremely lucky that I have a husband who is happy to stay at home so I can fulfill my career goals. It's what HE wants to do, and when he finds work that he loves or needs time off we find a way to make it work...together.
That being said...no your life won't be the same if you leave your children with another person during the day...but that is not to say that different is necessarily bad. Just because it will be different doesn't mean it will be different for the worse. When my husband decided to go back to work and our part time nanny/babysitter was unable to cover it we put ds into daycare (he was about 18 months). He absolutely FLOURISHED. Completely came into his own. This does not mean that all kids are suited to this, we got lucky in many ways, but you never know until you try. His verbal skills were almost non-existant and suddenly he was talking in full sentences. He ate meals better, started using the toilet by himself, and when we were home together we really appreciated the time together and HONESTLY I spent way more time with him when he was at daycare than when we were home full time and I was so sick of the sight of him I was forever trying to entertain him with other things that didn't involve me, or that required minimal mental energy on my part.
When I was doing my own thing and DH his and DS was in pre-school when we were together (from 3pm to 7am and all weekends and holidays -- as a teacher that's 3.5 months out of the year in all) I didn't want to take my eyes off of him. We cuddled and read,and went camping and spent days at the park and were a FAMILY in that sort of picture book wonderful family sort of way. It was so much better for us all. I had more energy as a mom not being a SAHM than I did when I was on maternity leave and around him all day long. I have found this maternity leave that bled into my summer vacation, exhausting. I am so looking forward to going back to work so I can truly appreciate and have the energy to engage in my relationship with my children again. At the moment I just feel so lost and so detached from who I am that I don't even like who I am around my kids most of the time. I too studied a long time to be where I am and have worked really hard to get where I am in my career. I'm a better, happier, more focused person when I am working.
I have always envied moms who make being a SAHM look so easy. I wish I could be like that...but not all of us can do that and it doesn't make you a bad mom, it just makes you a different kind of mom...ya know?
I'm trying not to make too many assumptions...but it's just a message board, ya know? It's hard not to fill in the blanks with your own displacements.