Is it okay or normal to be jealous if your SO talks about his female coworker every time he comes back from work?

My boyfriend and I see eachother two- three times a week because of different schools and he has work and I have other events. When we are with eachother we ask about eachothers day and sense he works a lot he tells me about his job and I know I should listen and support him but he talks about his coworker who's a girl and says how they don't have a filter when they talk to eachother and he gets along with everyone so everyone is with him I fear of her getting so close to him. She knows his schedule and knows him so well and I feel like I know nothing cause I'm not there. Sometimes I feel like I'm going crazy I think it's just me. Any advice?