I understand why you're so beside yourself. You both are dealing with a sea of emotions. You feel guilty and are questioning your love for him. At the same time, you're feeling annoyed by his nonstop calling and attempts to control you, which are themselves being fueled his feelings of hurt and mistrust.
Let's begin by saying that the fact that you cheated on him does not mean that you didn't and don't love him. I imagine that at the time you were feeling lonely and sexually frustrated. It is my sense that the alcohol helped you to lose control over your impulses. That is one of the side effects of alcohol: It lowers a person's inhibitions and defenses and weakens impulse control. It's not an excuse, but it is an explanation for what happened.
You will need to examine whether you have a tendency to drink too much and then act out. Have you acted out in the past when under the influence of alcohol? If so, then it would be good for you to go to Alcoholics Anonymous and deal with your drinking problem.
Even if you've never before made a slip while under the influence of alcohol, we still need to know whether you have a tendency to act on your urges even when you're sober. If this is an issue for you, then we need to admit that you have an impulse control problem and work on it. There are articles in my Advice Archives that will explain to you how you can teach yourself to develop impulse control so that you will never again say or do anything before thoroughly thinking it through.
I think that when your boyfriend discovers that you are taking your behavior very seriously and that you are working on understanding why you did what you did, he will feel much less fearful and mistrustful of you.
I would also encourage him to talk to you about his feelings. When feelings are not heard and understood, they have to go somewhere; then they become expressed in actions. In your boyfriend's case, the feelings of mistrust are being expressed in two behaviors (calling you nonstop and
controllingExamples of controlling behavior include within an intimate relationship include: one partner isolating the other from his/her friends or family; not letting ythe partner go out of the house, to the...(Click for full definition.) your drinking). I'm confident that he will stop acting his feelings out when you talk to him, listen and understand his feelings and finally explain what you're doing to address the issue.
Please let me know how you both do.