Husband still looks up his ex

 question... if you found out your husband STILL looks up his first love ex girlfriend from ten years ago on Facebook every once in awhile you would ask him about it? Idk what it means that he still looks her up or if it's nothing to worry about. His Facebook search was lying clearly unintentionally open on the computer and I saw her name. Clicked on the expand list (yea probably shouldn't have but I was just curious,) and saw that yep he looks her up every few months and always has. easy to see bc he only checks on the same couple pages. We have been together for 5 years, married for a year and a half, and have a one year old son. I'm a little hurt but maybe I'm just too insecure! I do know it took him many years to even get over her at all.