Anyone know of a fixative that actually works?

Polygrip do one for partial. Or you could try Wernets powders.

If you need a fixative then your partials don't really fit properly.

It's difficult with partial dentures and unless they're a tight fit there's nothing much else to keep them in. Try another visit to the dentist to see what they can suggest.

After years of dentures and trying to find the perfect fixture I gave up and had implants done. A couple of implants an a denture that fits into them and holds. Can eat anything now.

I find Wernets Ultra the best, Boots use to have their own brand which were as good as Wernets but cheaper, no longer available

Chiclets--as in the Dennis film, hahahaha.