make a tally chart of her reasons for not putting out. Wait a few months then show her, oh and film the reaction.
It 100% won't help your relationship, but it will be very funny for us
I know this is a well serviced piece of advice and I'm sure many will have heard it before however . . . . . . When I got engaged a bloke at work told me to put a penny in a jar every time I got the leg over, until I got married. He then told me to take a penny out of the jar every time once married . . . . . He claimed that I'd spend the rest of my life emptying the jar. I laughed at the time . . . . . . . . . !
Maybe my new years resolution should be to try something other than "lift thi nighty up lass"!