Well, I went through many of the thoughts you are going through. I alsways wanted more, the day Cedric was born I though "I want one more". But DH and I agreed on 2, so I let the issue rest.
It came up when I hired a babysitter who brought her 4 months old girl to work. Seing the boys, especially Jerome interacting with this little baby girl made me realize how much I still wanted another one. I wanted to see all of this with my own child.
I took my heart and talked to DH, and we agreed to try for one more. I got my IUD out, and got pg right away. As most of you know, I miscarried that one, got pg again, and miscarried again. The lat mc was in January 2006.
Since then I've been going back and forth for many reasons. We just got a house, I finally had my own room for sewing, crafts, office..... I started a new Job, childcare costs, how much time we would be able to spend with another one, trips to Germany, you name it. I thought I was ok with just the two I had, and then the anniversary of the second miscarriage's due date came. I got so sad, and moarned what I lost. This weekend is the anniversary of the first mc, and I am pretty emotional, and still sad about that.
DH and I talked, and we will try for another one, probably next months. It took me a long time to get him on my side, and for him he mainly agrees because it makes me happy. He will love another one just as much as the first two, but he doesn't long for another one. I however do.
As far as Aidan goes, and him not sleeping through the night, Jerome didn't sleep through the night until he was 3 and we figured out why he kept waking up. Cedric however slept through the night at 3 weeks old, so you never know what you get.
The possibility of you being on bedrest is a bigger concern, I think. You need to decide how much dh is able and willing to help out, and how you and the boys will handle the situation. Maybe you can start saving and be able to hire someone to help you out a few hours during the day, maybe even a high school student would do, and you can be on bedrest at home if possible.
You have many good points, but I think follow your heart, guided by your brain. If you think the situation is impossible, maybe two are enough. If you think it will be hard, decide if the joy of another baby offsets that, and if some of it being hard can be decreases by careful planning.
But selfishly, I would love a pregnancy buddy
