Relinquishing the seed

Should I have another baby?

Every six months the fertility clinic sends me an invoice for $225 to store the 11 vials of my donor's sperm that I have left. Since the last payment I have been considering whether I want to continue keeping the sperm, or let it go. It comes down to whether I think I will need it.
Which brings me to the question, do I want another baby?

At the moment, the answer is no, I have my hands full with Roma so do not think I would be able to give two children, the same level of time and patience I give to Roma. Plus, I don't feel the desire, or urge for another child, like I did for Roma. She gives me all the joy and love I hoped for, so there's no hole to fill anymore.
Yes, it would be beneficial for her to have a sibling to play with but I think the fact that I will be spending more quality time with Roma during her childhood, because she is an only child will be beneficial too. So I guess I have made up my mind, but still, it is hard to sign the paperwork to relinquish the seed. What if I change my mind? What if I get the urge again? This is possible, but thankfully I have Roma's donor in our lives, alive and willing to donate again if need be. So there's no real risk...but still, by signing that paperwork, I am taking a step, making a choice not to have anymore.

I wish I could transfer the vials to someone else, and I asked the clinic if I could do this, but it seems I cannot because they have identifying information on them. Because we conceived under a known donor arrangement, they could only be used with someone under the same arrangement.

A part of me is sad that I will probably not see Roma playing with a sister or brother one day, she loves other children. However since Roma was conceived, her donor has donated again to another clinic as an ID release donor, and since doing so has given life to 3 girls and 2 boys, so perhaps one day I will see my vision become reality after all.