selectable power port

I did a search but didn't find this specific question...apologies if it's already in here and I didn't see it...

I have a 2000 Excursion, and the power ports have power all the time.  I'd like to add a switch and relay to let me select if it will get power with the ignition circuit or all the time (so I can leave things plugged in to charge and be able to select what ports charge all the time vs only when the ignition is on).

I think I have the wiring down, but I don't know the switch I need.  In the diagram below, the relay would 'activate' every time the ignition is turned on, even if the switch providing the main power to the relay is set to bypass it:

Is there a switch I can use that would only provide power from the fuse panel when the switch is set to send power to the relay, preventing it from activating when it doesn't need to? 

Thanks!