Premature ejaculation issue

my boyfriend suffers from premature ejaculation we have been together for 4 years and it has only started happening the last 2 years i don't want to try anything from the AMI nasal delivery place because it's very expensive and would be a waste of money if it doens't work. i want to know if anyone out there has this problem and what they have done that has fixed the problem, we have tried kegal exercises and that didn't work and also delay sprays which also don't work.. please help us