how do seven jeans fit::I go up and down in size i usually am anywhere from a 812 but that is not the problem how do seven jeans fit

how do seven jeans fit::I go up and down in size i usually am anywhere from a 812 but that is not the problem.
I consistantly have a really hard time with jeans no matter what size i am.
I have tried trousercut, bootcut, straight, skinny, flare, and wide leg styles.
I have a defined waist.
Then out to what looks like saddle bags due to the indents.
My body type really never changes much it just morphs bigger or smaller in proportion.
I try to buy jeans that are midrise or low rise that have higher rises.
I make sure thaey are higher than the top of my hip.
I watch where the pockets are placed and also the size of the pockets.
I buy dark jeans.
I go into the dressing room and i feel as if i follow all the rules and i even find jeans that look flattering on me.
Thhe problem is when i actually wear them.
I do not have one pair of jeans that will stay on my hips.
Once they start to slide then the seat bags and i just hate them.
Please , please help me, am i doomed.
Do i need a custom fiited jean to fit my body type?