I'm very sorry for your loss, Phil.
Is your other bird male?
It definitely is a gamble introducing new birds as they may not get on. Having two cages is a must so they can quarantine apart in different rooms, and then live in their own cages when allowed in the same room together. They can only share the same cage once they are bonded - preening, sleeping together, eating together etc.
Introductions should happpen away from those cages.
Only bring a second bird home if you can be ok with having them live in separate cages should they not bond.
Sorry my answer is a little repetetive but the two cage thing is the most important, and there's no fool proof way to bond lovebirds aside from those with colonies.
Wishing you luck in whatever you decide