just want some opinions

Hey guys so a little background first. I dated my ex for 3 years (freshman to the end of junior year in high school) me and my current boyfriend have been dating for 4 years. (Senior year to now). There was about 6 months between the two relationships. I love my boyfriend to death. We have a house and a happy little fur baby family with two dogs and our cat. What I need advice/opinions on this. Sometimes I feel like I don't want to be in a relationship. I feel like I want to be single but I know deep down that I wouldn't be able to lose my boyfriend. Why do I feel like this. I don't like it I feel like a terrible girlfriend because I think about wanting to be single.