Booty touch

So me and my husband work together (he is a cook and I'm a cashier/waitress) well there is this girl there, let's call her ana. I have been very suspicious of the way my husband and Ana talk to each other. My husband is a very playful cheery guy, so he plays around with all the coworkers. Every time it is me her and him I here her screaming from the back (she is the dish washer) and I wonder to myself "what is he doing to make her scream" 😠 I have never liked her and I've always had a feeling about her. Well in the night I I have to clean everything right so I go to where she is in the back to get the soap and my husband is back there. As I round the corner I see him walking past her and it looked like he was going to grab her ass but caught himself when he saw me. He then tried to cover it up by talking about something but she looked totally confused like "what are you talking about?" My heart was pounding when I saw it and I just don't know what to do in so hurt. I need to ask him about it but how can u go about it without blowing up? Please give me some advise and some reassurance. We have a 6 month old beautiful baby boy, but my family will not be a family anymore if he wants to play around.