Normal ? Yes.
Good ? No.
My recommendation ? Turn the jealousy on its head and make it something good. Here's how that works.
Think about why you are jealous. It's because you REALLY like your girlfriend, right ? You love her a lot ! You want her to appreciate you and be with you. And you're worried that those other men are a threat to your relationship.
That's the first key right there: The fact that you really love your girlfriend, is a good thing, not a bad thing!
Let's look at the other part. Are they a threat ?
What kind of girlfriend would you rather have ?
Would you prefer a girlfriend who stays with you because she knows no other attractive males at all, and therefore she doesn't have much choice but to stay with you ?
Or would you prefer a girlfriend who knows and laughs with many attractive men, but who, despite knowing all these other men stays with you, because she prefers you, and because she loves you?
What is the best compliment ?
I stay with you because I have no choice, or at least no good alternative.
I do have a choice, and I do have good alternatives. My choice is you.
Think about it a little bit, hell, think about it a LOT.
Can you see the beauty ?