He is upset because he specifically asked you not to do one very specific thing - which you then very specifically, did. The details really aren't important. Your brother asked you to make an agreement with him. You agreed. Then you broke the agreement. That's the crux of your argument with your brother and if I were him I would also be very upset. In fact, I would write you off. Not as someone to be polite to - I'm sure he'll come around to that extent. Not as someone to send a christmas card to. But as someone to count on? To trust? He may never do so again. Why should he? Why would he? Haven't you pretty much made it clear that is the one thing he should never do?

He had his reasons for asking you what he asked you. And you had your reasons for breaking that agreement. Until you gain insight into why you would do that - make an agreement and then break it, over and over again - you have zero chance of winning his trust back.

Maybe one day you'll come to think it's important to keep the agreements that you make with other people - regardless of who is attracted to who when and where and why. Getting drunk for eg just won't cut it as a reason. Or, if you do come to regret an agreement that you've made you'll let that person know that the agreement no longer stands before you break it. Maybe one day you'll be more careful about what agreements you enter into. And then you'll be on your way to being a person your brother - or anyone for that matter - can trust.

it's no man's business who a woman sleeps with. Would we even be having this conversation if you were a guy?

Your brother is upset because he is your brother. It's kind of like your parents having sex. You know, theoretically, that it happens, but that's as far as you want it to go. What makes it even worse is that your brother doesn't even like this guy, specifically how he acts towards women. He's probably heard the sleezeball stories, and doesn't want his wonderful sister anywhere near that guy. And he definitely doesn't want to hear this guy brag about how easy you were, or what you did in bed (and yes, a true sleezeball will do that).

So....in retrospect you should have kept in your pants, if only out of respect for your brother.

That being said, your brother is way out of line for expecting to have any control over who take into your bed. He can make suggestions, and he can sulk, but that's really the extent of his participation. So I think you should let it go. Tell your brother that you are sorry that you hurt him, but don't say that you were wrong. Because you weren't. You are both adults and that's that.

However, this incident has forced your brother to confront an umcomfortable aspect of your sexuality, and fair or not, it will take him a while to get over it. It has also revealed a controlling, temper-tantrum-throwing aspect of your brother's personality to you, and it will take you a while to get over that. So bear with each other, and remember that in an odd way, you are now closer because you understand each better.

And in the future try not to sleep with your brother's sleezeball friends, at least not if he is going to find out.

Your brother can get over it. Yeah, you said you wouldn't do it and you did. Boo hoo. Life happens. Nobody broke vows, cheated, or otherwise compromised the sanctity of committed relationships. Your brother doesn't own this guy and can't dictate who you do what with. Even if your brother has a sexual relationship with this guy, you didn't know this. The cut-off because you did what he "told you" not to is just childish. He's overreacting. Apologize for going back on your word, but don't grovel. You're an adult, he's an adult. Move on and hope that he does too.

Your brother gave you room and board and just asked you to not sleep with his roommate. You did anyway. Maybe you should ask yourself what is wrong with you. Why is it that you were compelled to do the very act he asked you not to? Stop blaming him. Blame yourself. You can never go back.

If she's 16 or 17, his reaction makes slightly more sense than it would otherwise. I mean, hearing your sibling drunkenly having sex might be a bit awkward. (Or funny, depending on your family.) Plus, he might know something about the roommate that you don't. Like that he secretly films his encounters and they show up on You Tube. But still, daily weeping over this is a little strange. Maybe the roommate has something on the brother? I just feel like there's a backstory here that maybe even the LW doesn't know. Breaking promises sucks, but it sounds like the LW thought this was a promise along the lines of, "I promise I won't eat all the cookies" and the brother thought it was a promise along the lines of, "Upon my life, I will never ever betray your sacred charge."

"Well, you now know your sister is kind of wild when she drinks."

It was awkward but he'll get over it, and you should too. Next time keep your promises.

hmm....looking at your letter more closely, a few phrases pop out. After it happened, your brother "made you cry every day," made you feel like "the worst person ever," and "he will carry this sorrow with him for a very long time

In response, you want to "take away all the suffering he had to go through."

There is a phrase for this kind of behaviour- emotional blackmail. Your brother is responsible for his own feelings, and frankly, the way he's acting is not reasonable.

Your instinct is correct. You did a "perfectly normal thing." The way your brother is reacting and you are responding reveals some abusive dynamics between you two- you made a mistake, he made you feel worthless (for a month), he still refuses to forgive you, and yet you think it's your responsibility to make him feel better. It's not. You did make a mistake, but it wasn't really that bad and it doesn't deserve the kind of response that he's given you. Frankly, if you were his girlfriend, I would advise you to break up with him.

So...yeah, go ahead and apologize to him, for the last time. Then, if he can't accept it, let it go. His emotions are his responsibility, not yours. And at this point, he owes you an apology too.