this website can provide you with the internet service provider for that IP number. i suspect that if there is abuse going on you can contact the ISP and they can tell you who it is or give you some sort of information regarding the matter.
simply copy paste the IP number into search box and it comes up with the ISP information. http://www.arin.net/whois/
this is the information is generated: OrgName: Verizon Internet Services OrgID: VRIS Address: 1880 Campus Commons Dr City: Reston StateProv: VA PostalCode: 20191 Country: US
yup, checked it myself too. it belongs to verizon. that means whoever it is was or is using Verizon as an ISP. is she bothering you again? isn't she happy with your ex?