My new boyfriend ejaculates as soon as the head of penis enters me. what can i do? how long should he last?

This could be pre-ejaculation or just being able to perform at his age if he is as old or older than you. You can buy desensitizers at pharmacy or slowly talk and relax before sex. Have a few drinks before sex will slow him down.

Premature ejaculation requires evaluation by a Urologist or sex therapist. There is no set time for timing of ejaculation. It could be from 4-10 minutes depending on a lot of things.