Confused and hurting

My “x” and I had been together for 8 months.She has been divorced and at times felt that I smothered her.During this time she would ask me for her space, which I gladly gave. Things seemed to be going well over the past weeks, took her out to dinner for her birthday, went hiking and four wheeling; all things she really likes to do. While I was off on a business trip she called me to say that she wanted to stop going out. I asked her why,had I done something wrong,was it another guy,did I not make her happy. She could only say that I was a special person to her but that she needed time to get her own life straight. I guess what I don’t understand is the suddenness of it all and if she said she cares for me then why leave me.