I think you’ve written me about this before — next time, please link your questions together, so I can have more information about your history with your issues. 😉
As for your question here, it’s absolutely okay for a man or a woman to date more than one person at a time. In fact, it’s pretty efficient if you’re truly interested in finding Mr. Right. Serial dating can take up a lot of your time (and his). So the answer to your question is yes, you can date two guys at once.
I have to add, though, that ideally, you should decide in a couple of months of dating, whether or not someone is compatible and enjoyable enough for you to continue dating him. There’s a difference between dating to find Mr. Right and cheating. If you date more than one person for months and months and months and years on end, and you’re not upfront about it, you’re misleading them and that’s cheating. But it’s always fair game to date more than one person at a time for the first couple months of a relationship in order to decide if they’re someone worth pursuing.