Honey, this man has no business having this type of relationship with you. He's breaking every code of conduct rule there is by eating lunch with you, emailing you, getting involved in your personal life, and discussing personal topics, using foul language, etc. He's a married alcoholic in his fifties, who's risking his career by engaging in an inappropriate relationship with a student - this man has no judgment, and you absolutely can't trust him. Hon, he's quasi-suicidal - that means he's dangerously close to having nothing to lose.
If you were my daughter, I hope you would do the following: stop having lunch with this man; stop emailing him; stop having any contact with him that is not necessary to your teacher/student relationship. If he asks why, tell him your mother found out and she forbade you - that ought to scare the shiz out of him. And stop thinking about him. Stop fantasizing about him. Your imagination is working overtime to feed the feelings you have about him, and you have to stop doing that. When you start to think about him, physically stop yourself: shake your head, go for a walk, stretch, do some deep breathing exercises, learn how to say the alphabet backwards, solve a difficult math problem - anything to get your mind off of him.
Look, this isn't your fault, so don't waste your time feeling guilty about it. You made a mistake getting involved with this man, but that's completely understandable because you're a young lady with no experience playing for stakes this high. Now you've got to be the adult in this situation, and get yourself away from this guy. Good luck, honey.
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What you feel is what you are and what you are is beautiful...