How do you ask a guy if he is dating other people we have been dating for about 2 weeks should I just let it lay or ask?

Firstly, do you have a reason to think he is dating other people, or is it just paranoia? If you are just working yourself up, let it go and learn to trust a little. However, if you have a reason to think that he is, like a friend saw him out with someone else, go ahead and ask. If he is, and you act like you do not know, you are establishing that it is okay with you. If he does it in the first two weeks, and it is okay, then he will think it is okay after a year too. It will be much easier to deal with now.