Can I sued my ex boyfriend for giving STD herpies

Yes, as you can see there are such lawsuits being filed against various entertainers in the news like Usher. The main issue is whether the ex boyfriend knew he had herpies or not and whether he lied or failed to disclose to you that fact. If he did not know he had the STD when you were together, it might be more difficult to prove that he failed to inform you.