Talk to Gynecologist on Low Sex Drive And Lack Of Interest

hello, i need to know about the cause of this issue, its been 4 years since we married and ever since my wife has not enjoyed the physical relation and she has lack of interest in making physical relation. we are parents of one son and he is 2.5 year old. recently we visited a doc and discussed the issue she advised some anti oxidant. after 2 month of medicine usage still there is no improvement in her condition. My wife also facing some issue regarding anxiety and ocd issue. i wanted to ask about the best treatment for this issue.