Is this bad?

My boyfriend has this friend that’s a girl and I saw she comment on his Instagram posts with ‘cutie💕’ and he tags her in things and they have full blown convo in the comments where she says she’s heartbroken or something and he says it will make it up to you 😉’ and like idk he’s never spoken about her and they just seem like flirting am I overreacting or should I ask him about it and tell him I’m uncomfortable