How can I overcome feeling uncomfortable when my boyfriend laughs with other women?

The title pretty much sums it up. I'm a 22-year-old female (turning 23 in 5 days! :3), and my boyfriend is a 28-year-old male. We live together in a small camper, which is essentially just one room, and he works from home. This setup isn't ideal since I'm at home for school, meaning I have to stick to my desk during his work hours because he needs a quiet space without distractions (which I totally understand). As a result, I overhear all his calls, and about once a week, he has a meeting with his manager—a woman. Their conversations often start off lightheartedly with casual discussions before they get down to business about what needs to be done. What really bothers me is how much he laughs during those calls. I think it triggers my jealousy, especially since she’s another woman, and it makes me feel insecure to hear him having such a good time. Even though I try to rationalize it, sitting at my desk and hearing him giggle like she's the funniest person ever really gets under my skin. I want to learn how to handle this maturely and move past these feelings. I also know he’s probably just trying to impress her for a promotion. Rationalizing doesn’t stop my feelings of upset, but I don’t let it affect our relationship, nor do I mention it to him because I recognize that it’s my own issue. I wish I could just let it go. It doesn’t help that he jokes around with other women too. He got somewhat close to one coworker, even calling her "by far his favorite," which I stumbled upon. He explained that he was using her to gauge what others thought of him, I guess because he believes people might be envious of his work performance. Since then, I've felt increasingly uneasy whenever he talks and jokes with any female colleagues, including his manager. Edit: I probably should have titled this "with other women." My bad!