My ex girlfriend abruptly dumped me earlier this month on our way home from a double date with her friends (we dated for about 5 months). I was shocked because things seemed to be going really well, she had been talking about a future with me and moving in together in the spring. She is 34, I'm 30. After she dumped me, she sent a lot of mixed messages, such as kissing me when she came to drop my stuff off, then asking me out to dinner. She also called me for comfort before starting her new job, called me everyday after that, including Thanksgiving. Last week she asked me to go out with her, her friend and the friend's boyfriend. After, she and I went to dinner alone and she asked me to stay the night with her. The next day she made plans with me, only to break them an hour before we were supposed to go out, she said we shouldn't talk anymore. 4 days after telling me she didn't want to talk anymore, I ran into her sister, we talked for a few minutes, but we did not talk about my ex at all. Later that night, my ex called me to say she heard I ran into her sister, that her sister and family missed me and think I am so nice. She then asked me what the sister and I talked about, and proceeded to ask me for advice about her new job, which I helped her get (she dumped me a few days before she started her new job). The conversation ended up in an argument because I asked her why she wanted my advice and why she was calling if she didn't want to talk to me just 4 days earlier. She also offered to decorate my new apartment, which we were going to do together originally. I got mad because these feel like mixed messages. I asked her what she wanted from me, she said nothing, and wanted to be friends. I told her that would be too hard because we both would get mad at the other when they start a new relationship. She was offended that I signed up for online dating so soon after her dumping me. I don't know why she cares since she dumped me. I miss her and don't know how to handle this.
Why would she say I'm everything she wants and then dump me? Why say we shouldn't talk, then offer to decorate my house?