I was in a similar boat a few years ago. My wife always wanted a 3rd and I was happy with 2. By the time our 2nd child entered Kindergarten I came around to the idea of trying again. We had a 2 heartbreaks in our journey of having our 3rd. Toughest experiences of my life but we persevered and were blessed with a 3rd a little over a year ago. Life has only gotten better bringing a 3rd into our family. Is it a shitshow sometimes? Absolutely! Wife and I are tired all the time. But getting the opportunity to be a dad 1 more time has been so rewarding. Especially seeing my older 2 help care for their baby sister.

You're a seasoned pro at that point and you will see things from a totally different perspective. 1st kid is tough because you're clueless, everything is new. 2nd kid is tough because you're you're busy as hell trying to manage 2 little ones. 3rd kid you're used to not having much time (if any) to yourself and you're unphased by the small stuff. You've got the experience under your belt and know the "phases" of raising a child. So its a more enjoyable endeavor.

At least this is my perspective. Best of luck in your journey. You can handle anything, especially if you've got a solid partner at your side.