My boyfriend's mother ran a background check on me!

She has always been super controlling and very jealous of my relationship with her son. we have been together for 3 years and the on the telephone.she admitted to having had a background check run on me recently. why? I don't know. other than.the fact that she thought she would find something out to ruin my relationship. she found nothing of course. told the boyfriend and he seemed kinda nonchalant about it while I am so so so mad! how would you feel and how would you deal with this?