Recycling old boyfriends can be very disruptive. You always prefer to give a prior relationship another shot, but most of the time people don't change. It's natural to go back to what your familiar and comfortable with. Yet, the worst part is that when you invite a past partner in your life, it can prevent you from either moving on to someone new or worse, having a negative impact on your self esteem and depleting your energy. It's about you at the end of the day and you need to have a healthy approach as to who you allow in your life and who you put the "kibosh" on.
It's better to be alone then to be with the wrong person. Being in a dysfunctional relationship is much worse then being on your own. The ability to start fresh everyday is a gift! I enjoy the single life freedoms and indulging in my own interests. In the same breath, I will never give up on love and one day having a lasting relationship.
As a good friend of mine once told me,"life is exciting when it's confusing because you never know who might be right around the corner."