right around the time the girls turn 1.25~1.5 or possibly even as late as 2, you and the wife will be discussing the dreaded "are we ready for another one?"
and that's because having and raising kids is amazing. i was one of those guys who always knew he would be a dad and wanted to raise a kid, so take this with a grain of salt, but kids are awesome. in my line of work, shit goes up and down like crazy (along with the stress), and my one constant has been my daughter. you can pour your heart and soul and love into your kids... it will be like shining a flashlight at the sun because of all the love you feel from loving them will make your efforts seem laughably feeble in comparison.
now, like i wrote on your facebooks, this isn't to discount the utter shitfest your life will be (at least sleeping wise) for the next 3~6 months. that is a "joy" i could have done without, but ultimately, it contributes to the overall experience. there are lots of other things, but you're living it now, so no need to tell you. wish you guys the best.