My twins are from IVF. We'd talked here and there hypothetically about having a third & wondering if we'd do IVF again. My girls were still nursing & I wouldn't do IVF until they'd weaned, so we weren't really thinking about it. I had a surprise pregnancy right after the girls turned 2.
I spent my whole pregnancy with Ian ambivalent. While I was very happy to be pregnant and glad he was a singleton, I wondered how I was going to handle it. One of my twins is really a handful. I felt completely overwhelmed by them some days, and still do.
Ian has been just a dream. He's a pretty mellow little guy, though, and if he'd been high needs, I might have different feelings about our situation. He's generally happy, loves to be worn, nurses well, is able to sleep on me out and about and is a snuggly little co-sleeper. I didn't co-sleep with my twins for very long and did not wear them nearly as much as I wear Ian, so it's been a nice experience for me to mother one. It's been easier for me to have one mellow infant plus two not mellow preschoolers than it was to have two infants.
But, if we'd just had twins I would have been happy with that, too. After two years of TTC and countless shots, ultrasounds and tearful moments wondering if I'd ever be blessed with children, they're a dream come true.
We do toss about the idea of a fourth, mostly because neither of us are willing to do any permanent birth control, but I don't think I could handle 4, really. DH works a lot and I'm 37! I think we're done. Maybe when the girls are in school, assuming we don't home school.