easy , start going to the pub every night with your mates after work and dont spend anytime with her and when she starts moaning like fuck (which she will) just tell her shes doing the same with her mate every night and it gonna stop until you start spending quailty time together , basically play her at her own game but up it to the next level.

p.s if she dont mind you going to the pub every night then this plan is totally fucked