I lied about finishing during sex

so my boyfriend (17 y/o) and i (16 y/o) have been together 3 months and have sex a lot... I've maybe finished once during and it wasn't even with his penis it was with his hand... he has finished every time we have sex. i enjoy the sex sooooo much but i can NEVER finish and I don't know why? he's REALLLYYY upset about this because i told him that i have finished a lot more than once and i JUST told him that I haven't finished every time.