I think the overall family dynamic would be easier when the twins are b/g twins. Same sex twins, this seems more complicated. So if your 3rd is a boy, he has a brother bond and if it's a girl, a sister bond. It's not the same as a twin bond, but can be. Also, all your kids would be similar genetically (meaning, no one is identical).
I think this dynamic is harder with same sex twins, and even more difficult with a set of identical twins. Of course that doesn't mean IMPOSSIBLE, just a few more degrees of challenging.
Now, would you have wanted 3 if they were all born at different times?
If I'd had twins, I would have stopped. If you are paying for 2 kid in daycare at the same time and still want another, go for it

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