I truly can understand why. You say that you want a safe, stable and loving environment for yourself and your son, but you admit that you have cheated on your husband, and have feelings for a man that is unhappily married and says that wants to leave. If you want to be single and see other people, then divorce your husband. You are not teaching your son to grow up with any morals or ideals by cheating on his father, and wanting to date married men. I highly suggest counseling for you to learn why you feel a man has to prove his love for you, and why you feel that you have spent the past 7 yrs.
Marriage is about communication and trust.
No one is perfect and it takes a lot of time and understanding to make it work out. Counseling will help you learn why you feel the way you do about your relationships and help you feel better about yourself. Until you learn to feel confident and good about yourself, you will never find what you think you are looking for.