I think that the bond that you have created with your son by spending so much time with him is the cause of his wanting to be with you rather than his dad. You mention that your husband does not spend much time with your boy; even a two-year-old senses who is happy to be with him. As a matter of normal early child development, it's very typical for a toddler to exhibit a preference for one parent, even when both parents spend equal amounts of time engaging their child. It's also normal for a young child's strong preference for one parent may abruptly shift to the other parent for no apparent reason. However, given your marital problems, I'm not surprised that your husband might be accusing you of being the cause of your son's lack of affection for him.

Although a two-year-old is not developmentally sophisticated enough to understand that his parents are having serious problems in their relationship, he can certainly internalize the tension, anger, and arguments that occur between you. A tense family environment can contribute to a child's becoming anxious, fearful, and clingy. Please ask for help in your counseling sessions regarding parenting your son. He doesn't deserve to be caught between your current unhappiness with each other. I hope that you know that your "prize" is your little boy. Keep your eyes on the prize as you both make an all-out effort to heal your family.