Consider having separate top-sheets + blankets, perhaps with an over-layer blanket over all of it. Then, your partner's tossing and turning will jostle the bed, but won't pull on your cocoon of blankets (and vice versa).
*Note that this is usually considered uncomfortable and possibly bad for your back. I'm a side sleeper who always had elbow and shoulder pain in the morning and it worked for me, but do your research if you ever decide to diy a mattress. It also weighs about as much as a dead moose.