I have never given my boyfriend a hand job because I’m afraid I’ll hurt him.

You don’t have to be afraid you’ll hurt him with a hand job. The sensitivity of his penis is comparable to your vulva. The shaft of the penis is comparable to your outer lips, the glans is as sensitive as your clitoris. When you masturbate you don’t feel any pain, do you? So your boyfriend won’t feel pain when you stimulate his penis. Girls are often too careful. Guys like a firm grip. Maybe you should talk to him and tell him you are uncertain about what to do. He can show you what he likes and doesn’t like. If you watch him masturbate, you can imitate his movements.