as you know i have no way of examining your boyfriend's large testicles over the internet in order to specifically comment but a large scrotum may not be normal. he could have a large hydrocele (a fluid-filled cyst) or even a inguinal hernia. and it is also possible he just has large testicles. i would recommend that he have them examined by a good urologist.
my boyfrend has x large testes look like a small pillow in his pant he 62 been this way all his life is this normal? . he says they don t bother him its just embarrassing because its so noticeable even when standing but sitting down its really bad i ve known him 30 years and its always been this way its a lot of skin but the inside is firm and size of an olive.