Big Love n Big Sex

My bf is 400lb 6'1 im 200lb 5'5 myself so this isnt a weight thing. I really adore him. I know sex isnt everything it isnt, but anyways he does have an average dick size. I need sex positions. missionary is a no go and me riding gets to point my thighs hurt from being well spread apart so much and vaguely touching the ground. Please dont judge me.