Letting the ex get to me

The ex probably was drinking again and harrassing me over the internet.  My son went online when I went to bed for a few minutes.  He is 15 and likes to look up gaming info etc...  Well, the ex came onto the IM and was asking him questions, like I though you were going to bed etc...  Travis uses my screen name BTW.  Travis said it was him and Dave called him a liar and said he was contacting his lawyer.  Travis came and got me and Dave was getting nasty saying it was me all along, Travis doesn't type that good etc...  Saying Sarah doesn't get enough sleep, blah-blah-blah.  So I went to bed without fighting with him.  He sent me to nasty e-mails relating to Travis and Sarah.  Saying Travis is probably looking at porn and I'm a liar etc...  Saying that Sarah's teacher and Dr. are going to be summoned into court.  Sarah is being badly affected by my parenting and thats why she isn't doing well in school.  Not that she may have ADD.  Now he has me all upset and anxious.  I hope you are happy buddy.  To set the record straight, Sarah gets normally 9-10 hrs of sleep a night.  She is not falling asleep at school as he accuses, that was a one time incident.  Travis does not look at porn on the internet, I moniter what he looks at.  If he does summon the teacher and Dr. it will get him no where except to make me look like a good Mom because I'm the only one that takes Sarah to the Dr. and the only one that has gone to the school meetings and calls the teacher.  He has only gone to one parent/teacher conference and that was probably because his lawyer told him too.  So ok, enough of this rant....