His female boss does not greet me when we meet,could they be having an affair?

I have been married for eight years now and have three children. My husband works for an NGO and things had been moving on well until he started getting very close to his boss who is 14 years older than him. He now comes home late at night claiming to be from a business meeting with her and he says that he has to keep up with this to keep his job. He started drinking and our intimacy is now dead. His boss does not respect me and does not even talk to me when we meet. He is the breadwinner as I am a housewife but as time goes by, I am feeling helpless by the day. I have tried talking to him about this but he becomes defensive and worked up for no reason at all. He no longer listens and does not even seem to care about me. Please advise…