It seems to be one of the hardest things to do in a relationship, talk about whats not working in the bedroom, or, what is ok but could be better, but its a discussion that has to happen for things to change.
Insanity is repeating the same action, expecting different results.
Talking outside the bedroom seems to be the most accepted non threatening way to broach the subject.
As you seem to be keen to please him, it may be a little easier, but tell him you are open to making things better, you can either tell him what you are prepared to do, or, what you are not prepared to do (ie, we can do anything but.....).
Maybe you could try one of the adult games sold here on Lovehoney that has various positions, kinks, activities etc?
It doesn't sound like he wants you in control, so tie / tease may not be a goer, but it comes down to that chat about whats on or off the table.