Trust issues

So tonight I'm laying in bed with my laptop reading blogs and  seeing what's going on with everyone,  well the stbx walks in and asks what I'm doing. Thinking this is something I like to do I close my laptop. She gets offended  that I won't show her, so in the best interest of saving a stupid fight  I show her. Then She is like no big deal whatever I don't care.  So I ask her if she has a support group and she's like yes but it don't matter anyway.  So why be upset a out me having one ? Will I ever get this figured out ?