Help! Ex is threatening to sue me!

I found out my Boyfriend was two timing me, I emailed the other girl that we needed to talk etc. I asked her she freaked out that he was two timing her actually first! Anyway, he now claims I hacked into his email account and is calling his attorney first thing. I am very scared he has much more money then I do. MY internet is open and he has been known to be rather stalkerish and I am afraid he parked on my street, used my internet and hacked (guessed the secret question to reset his password) his own email. He is now mad that both of us found out and he wants to get back at me, since I found out first and told the other girl.

Am I facing thousands in legal bills for something he is making up???