The journey to my first was pretty smooth - a few bumps before finding my surrogate. However, in my journey to number 2, I would say there have been many more BIG bumps... OK, more like mountains - very discouraging. But for me, it was never discouraging enough to stop me from having a second journey... and I have some stories meant for the presses. Now, I have found a wonderful surrogate - it took a while to get to her but she was just there waiting for me to find her.
Yes, if I didn't find her, there would have been a natural point where I would have stopped - I have an age where I would stop having babies... more accurately, I believe in a certain age gap between myself and my kids that would not be beneficial to my kids.
Good luck to you both!