Can it be called cruelty against husband

We are married for 6 years and have a 2 year old son. Last 5.5 years I was doing Ph D abroad, while my wife accompanied me. We had ups and downs, as the pressure of my research increased. After my son was born, my wife almost single handed raised him, when I was at the last phase of my Ph D. After finishing, I came back and started working. I hoped to return to normal life gradually. Unfortunately, that is not happening. She blames me at every chance for not doing my duty to my son - which I am willing to do! She does not allow me to sleep together. We don't have any physical relationship left. She just rejects me. I cannot communicate to her my feelings verbally. I tried to write to her to share how I feel - only to receive more humiliation. She takes care of our son all time, but has no time to spend with me. I suggested that I want to share some of her workloads - but it was difficult for me to maintain regularity due to change in my work time - and got farther abuse from her. None of us is happy, and what I feel dangerous, is that she releases her frustration by hitting the child badly some time. I cannot sleep at nights. My work hampers, and she blames me for being selfish! If our son were not in the middle, we would have definitely got divorced. I am confused whether there is any legal aid to help me in this situation?