I Am Having Séx With My Girlfriend's Boss'' What do i do?

I have a girlfriend I love to bits but I keep having séx with her boss. I run two men’s hairdressers and I met my lover when I first set up the business five years ago as she works for the hairdressing suppliers. She’s 36 and I’m 39. She made a late run to bring me some shampoo etc one evening and I invited her for a drink as a thank you. We got along well and after two bottles of wine our friendly chat progressed to flirting. Back at my flat, I made a pass at her and then took her to bed. She was an amazing woman with a body to die for. I thought it was the start of something but she then confessed she’s married. She was still the one to bring me any new supplies though, and sometimes she’d be up for a quickie, which was great. She invited me to a party at hers one night and she introduced me to her husband - and new assistant. She’s 26 and pretty and we spent the evening together. I asked her out on a date the following week. We’re now together and I’m crazy about her, but I still can’t resist her boss. My main salon is on her way home so she still usually drops off the supplies, normally at the end of the day. Once I’ve turned around the closed sign, we end up having séx in one of the barber’s chairs or in the back room on the floor. I feel so bad for my girlfriend. She’s oblivious to my affair but her boss keeps drawing me in