I know this is a question lots of people have about surrogacy. I got this question several times, and it was my mother's main concern when I told her I was going to do surrogacy. It's also, I'm sure, a very real worry that many potential IPs have when going into this process.
Here is a short article I found, written by a former surrogate to potential IPs who may be worried that their surrogate will want to keep their baby, or at least have a very hard time giving it up once it's born. I really liked this article because the way she felt is the same as the way I felt, only written more succintly than I would have done it.
Paragraph 6 ("Here's the key...") was me 100%. That's exactly what I wanted out of my surrogacy journey, and probably part of the reason I didn't feel fulfilled once it was over. I was hoping to be able to bask in the glow of my IPs' joy, and I didn't really feel like I was able to do that.
Here's to hoping next time turns out better!