Dear (enter name here) 

Something heavy has been on my heart for quite some time now. You know that I constantly try my best to love you to the best of my ability and to create an environment where we can both flourish as human beings and live our best lives. 

That said, it is with great sadness that I need to tell you that I am failing in that department. On a daily basis I see and experience exactly what it is that you need to feel loved and live your best life. Subsequently I realized that I cannot give any of that to you. 

If I choose to continue pouring myself into the future of this relationship, I will lose parts of who I am. Currently, I am loving you at the cost of my personality and my being. 

I truly believe that you deserve someone that will love you more naturally. 

This does not mean that I do not love who you are, just that I do not see our personalities complementing each other anymore.

All my love 

(your name)