Unbelievable

I have been so nice to this man. But yet he continues to cheat on me. What is going on in his head I am so outdone. He continues to cheat with prostitutes over and over again. I know since 2011 but now I am wondering if it has been longer. he refuses to take me out but yet he is taking this woman out over and over again that he should not even be talking to. How and why did this happen to me.