So my fiance came home...

& I was doing his laundry and found a girls number in his pocket. He works in the Deli at Walmart and said he was just doing his job and out of nowhere she was like here, here's my number. I want to belive him but it just seems fishy I belive a guy would do that and he's not really the type of guy to receive a lot of numbers. I mean he's handsome in my eyes but a lot of people don't think so. Should I just let it slide or what should I do? No rude ass comments either. Thanks