Tough one! I think though that sometimes there will never be the situation where everything just 'falls into place'. You just have to work out how badly you want it & if you want another one enough, then just go for it. You will find ways to make ends meet. Mind you, I don't have twins on my hands, nor do I have to work full time (I work from home, so I am very lucky that way).

It sounds like you are doing a great job with juggling life now, I'm sure you would still do the same with 3 (maybe you get extra superpowers with each extra child! I'll have to find out!)