I'd second the recommendation for something double sided, and double wide if you're the romantic type
We sleep in temps between 20-80F (mostly under the stars) and I've been really happy with this: https://www.bigagnes.com/Products/Detail/Bag/DreamIsland15
Lots of insulation on one side and double thickness thin fleecy fabric on the other. 2 side zips are key to stick a leg out without freezing your partner. I keep this bag and 2 full size pillows in a 24 gal action packer and it's an amazingly comfortable and versatile system.