Full Stop of A Possible Relationship

Can we have a relationship work and yet keep private space with us? Pei Wen is a girl whom I have been in contact since my relocation in San Yi. Back then we were just friends occasionally hanging out or having dinners together, sharing things with each other. When you are under stress due to workload, feeling down because a relationship doesn't work out or life doesn't go your way, it helps to have a special friendship like this. It was relaxing and comforting, yet not strong enough to proceed to the next level. Even when she resigned sometime after we met, somehow we didn't even contact each other anymore. I guess we decided to just let go and follow the situation. However, in order to pay back the respect of her giving me a happy returns of the day, I sent a wish on hers as well. That was the start of our reconnection and it gradually became frequent. Four days after the Chinese New Year, she called and informed that her mom passed away and wished to meet up. Since then we met once a month, three weeks, two weeks, and then one week. The feeling between us developed from friendship to a bit further more. We were almost together with just one word. Last Saturday night after our dinner, I did a bit shopping and then drove her home. Before I left we stayed in my car taking our time chatting. Just when she asked me to spare every Saturday for her, something got into my mind and made me feel like "huh????" She kept on talking and talking, but my ears couldn't take in anything. All I was thinking were: "she's not a happy girl," "as she said she just needs somebody accompanying her," "she's not that into me," "in all of our conversations I do feel that she doesn't really care about me and my life, besides she's a bit willful and not understanding in some of my situations," "she's not willing to exercise, so the reasonable prediction is she might keep asking me to spare all my free time just for her instead of triathlons and marathons with friends. Let alone persuading her to join me." "No I can't make it," thought to myself while on my way back home. "I can't give up something like that!" "I can't change my life just for a relationship even I myself am not sure of," "No....no.....no no......." I totally cooled down. Next day I went bike riding with Zhi Wei and I spit this out when we took breaks. He's quite a good listener, and gave me some very helpful and reasonable thoughts. On Monday I replied her email and frankly told her about what I think. Her response was not that big, but the pacing between us seemed to have stopped since then. I'm glad I made this decision. I want to keep my life going. Unless somebody is willing to join me, grow up with me, enjoy life and exercise with me, I will never change it a bit.