I am married and I want to know if we get an legal separation will he be able to date

The question is, "Who is going to stop you?" People date other people even when they are married, so being married obviously doesn't stop a lot of people. There is nothing that anyone can do to stop you from getting married.

With a legal separation, you will still be married. I hope you tell your date that you are still married.

Now, that doesn't mean you're a "class act". In my opinion, if you're married, you shouldn't be dating.