It's been a favorite for a long time.
Diarmaid Ruaidhri is nice, but I think it's a bit too Irish if you live in not
Ireland. Although if you live in
Ireland, then I suppose it would be fine. So if you live elsewhere,
Diarmaid Rory would tone it down a bit.
If you wanted to pair
Diarmaid something with
Mairead Aurelia (which is lovely, by the way), I suggest picking a middle name for
Diarmaid that goes along with
Aurelia. So something Latin-y. And I don't think the fact that they both end in D is bad, especially since they don't sound the same at the end.