hi, Sister.
I'm new to this site and a 'Virgin Poster' but was very interested in your situation. When my husband and I met 14 years ago (ouch!), we both wanted a big family. After a few years of marriage I became pregnant and we had our son and after a year or so. I was quite keen to have another baby. My husband, however, was dead against it, which upset me greatly. We had enormous relationship problems after our son was born, to the point where we almost decided to separate. I think these were caused partly by the total shock and change in lifestyle all parents experience after suddenly becoming totally responsible for another human being, and the fact that he went through a bit of a mid-life (at 30!)crisis. Anyway, I did become pregnant again and our daughter is 2 years younger than her brother BUT it was very hard in the beginning. I have always assumed complete responsibility for the home and the children, despite, in the early days, working full time myself, so I didn't really get a break and was exhausted a lot of the time. Also, if we had a row (and there were lots!) about the kids, my husband's ultimate argument was always "well you are the one who wanted more children" : true, but still hard to take!
Things gradually improved and my husband loves the kids to bits and as they grew a bit older, began to get more involved with them. Then, after 3 years, I began to yearn for another baby. At first, he said no, even though he acknowledged that he has none of the physical stuff to do (broken nights, nappies etc) and then, after much persuasion, he said he would be prepared to consider it later in the year, and when baby number 3 came along late last year, he was surpisingly delighted. I don't know if its just to do with maturity or the fact that he is much happier in himself after changing jobs, or the fact that our relationship is so much better these days, but he loves the baby to bits and is much more involved with him (tho. still not getting up though night etc.) than he was with the other 2 when they were little. I have to admit though, it was a pretty big risk to take and whenever I mention that a fourth might not be out of the question in a few years, he changes the subject pretty swiftly!!
Good luck Sister, and I do not think you are selfish for wanting more kids, just be prepared to live with the consequences.