Should I let my 5 yr old decide where she lives?

My ex husband has been asking me if he can have his turn with our daughter. We have been separated for almost 2 yrs now and she lives with me and visits him twice a month on the weekends and for summer break. He wants us to sit down with her this summer and ask her who she wants to live with and where she wants to go to school. I do not think that this is fair for a 5 yr old to make this decision or more so that she is obviously not mature enough to logically think out her choice. He disagrees with me, and says she should decide and I shouldn't dictate everything anymore.
I see his side and couldn't imagine what it would be like to be a weekend and holiday parent but I want to do what’s best for her, not what is best for him or me. I'm so confused about this and really just don't know what to do. I consider all the what if's but they only confuse me more. I don't want my daughter to think that I didn't want her because I listened to her at 5 and let her live with her dad but I also don't want her to resent me because I didn't let her go. I tell him that if the day ever comes that she wakes up and says she wants to live with her dad and can explain her thoughts and reasons why then yes I will be hurt but I will let her go.

Thoughts/Suggestions?