Guy here. I picked it out on my own but was given fairly specific instructions on what she likes. I did deviate a little bit but not much. For example, i was told she wanted a 3 stone because I have 2 kids. Its basically a family of 3 that she would be joining. I was also told that she strongly prefers round diamonds over princess cut.

I did pick out a white gold 3 stone ring with the central diamond as a round, but for some reason I just did not care for all 3 stones being the same shape. I had to mix it up. So its square-round-square. With the side stones being about 1/3 of the center.

She got the most important stone round like she likes. She got white gold. She got the 3 stone but it still has little bit of my personal touch.