Someone is searching my IP addy

[SunShineLover]

I am not the most technology savvy person but I know a little.
I had a blog on blogspot with a statcounter on it.
I found out my ex (three weeks ago we seperated) typed in the IP addy and was doing a google search.
He found a forum I post on.

I am now worried he will do something else.
I have windows xp
Internet explorer
Norton 2006 but it has expired. Yes I know I should renew it.
I have already changed all my passwords and I don't keep the remember them clicked on the computer. I need to add them each time.

I called internet provider but they cannot change IP addy.
I am thinking of going with a different provider.

My main concerns are what can he do to my computer with this info and how much can he find online with my ip addy.

TIA