tossing and turning + sore hips when sleeping on my side

We have a double bed - with wooden slats.
I am 8st 3, my husband is 9st 7 - when sleeping on my side, my hips get very uncomfortable.
My husband sleeps much better than me, I tend to toss and turn quite a bit.
We slept on a memory foam mattress on holiday - my husband got too hot and felt restricted when he sunk in.
I just want to get a good nights sleep!
We do not have a large budget... what do you recommend please?