When you can't fully commit just in case there's something better

What if there's a better job or partner out there for you? Why in the world would you commit to what you have when there's a chance someone or something better could come along? Why commit to anyone or anything ever again when you are plagued with the fear that you may not have the best you could get? What if this isn't the person I'm supposed to marry? What if I buy this house but a year later I realize I don't like the city? What if I commit to this job and it turns out I hate it? I address the "What if?" game in a way that makes you think, so you can stop thinking "What if?"