Need mattress help

I’ve read the shopping guidelines on this site and still feeling overwhelmed. Could I get a mattress recommendation?

Current mattress: 15 year old Ikea sultan Finnvik, served us well but it’s sagging a lot now.

Me: 100lbs, 36 years old, side sleeper mostly, sleep hot, latex allergy
Husband: 160lbs, 38 years old, stomach sleeper. He doesn’t like springs, and prefers a firm mattress.

How long should I expect a mattress to last? I wouldn’t mind spending more for something that will last a long time and that will allow us both to sleep comfortably. Any brand suggestions?