Why does my iPhone 15 keep muting the other person during FaceTime calls with AirPods?

I use my iPhone 15 (relatively new) to ft my long distance boyfriend. However whenever we are on the phone it always cuts out and he ends up being muted and I can’t hear him. I wear my AirPods to be because there comfortable but why does it constantly mute him it does this without headphones and I’m getting sick and tired of it because FaceTime is the only way I can talk to my boyfriend.

[Re-Titled by Moderator]