Well I don't regret it. DC3 is wonderful, bright and beautiful. I couldn't ever say I regretted having any one of my children...
However she was completely unplanned and it did turn our worlds upside down. We had two DC 15 months apart which was planned, we wanted two close together. Then when DC2 was six months old we found out I was pg and just couldn't believe it. Astonished. Contraception failure, I always thought they were mostly made up and what most people actually meant was "forgot/didn't want to use anything" but no...
Most things are designed for a family of four. Family tickets are two adults two children, seats on a train with the table are four. We have to get a people carrier now if we need a taxi which costs more and is a pain because often there's a long wait on the people carrier... It just upsets a lot of things. Also there's the bedroom situation. Realistically the youngest two will always have to share a room, I don't see us ever moving to a four bedroom house anyway. And there's a middle child now, I feel overly anxious about so called 'middle child syndrome' and as it goes middle DC is the most highly strung of the three but that could just be personality and naff all to do with being middle DC of course...
There's also the hand situation. I only have two arms and often wish I had a robotic third arm. I can't hold everyone's hands when we go out. Atm youngest DC can still go in a buggy but won't be able to for very long so when she's out of that I'll have to trust eldest DC to walk holding middle Dc's hand or by himself which sends my anxiety through the roof. Keeping my eyes on three at a time is often a lovely challenge too. I have lost sight of the eldest before now, cue heart stopping panic.
It's also just way more expensive. Whenever I have to buy anything I have to buy three lots. E.g a trip to the zoo is a family ticket plus one extra child ticket rather than just the family one. When it's time to buy the autumn/winter wardrobes there's three to buy for. Christmas, three birthdays a year. A good example was something I want to get them all for Christmas only costs £25 but I have to buy it x3 so it's £75. £50 doesn't make my head hurt so much but £75 is just...
We needed a six seater dining table too. We'd need that if we only had two DC and had guests to dinner but we don't so our four seater did us just fine until DC3 upgraded to a booster seat on normal chair so we had to get a six seater, more expensive. Wanted a table and chairs for the garden, also more expensive as a six seater.
Sorry, this has turned into a bit of a rant. It does upset the dynamics of things though and the world is kind of adapted for a family of four. The world? Well, certainly this country and I imagine other first world ones too. I still wouldn't change a thing because DC3 is lovely of course but we did make life hard for ourselves and I wouldn't have chosen to have more than two.