Losing sensation?

Okay so i cant cum during sex or even oral (my bf is amazing at it i just cant finish) but i can cum while masturbating so do it all the time. Me and SO bought a bullet vibe to use during sex to get me off and yass it works but i masturbate with it too. Does it cause loss of sensation if you use it too much? i feel like i'm letting my bf down cause i can only cum with a vibrator 😭😭