I hate his friend

I have been in a relationship with my boyfriend for two years. Let's call him Steve. We moved in together a year ago. We have talked about marriage, and when we are ready -- both mentally and financially -- we hope to grow old together. There is one problem I just can't get over: his best friend.
They grew up together, and I realize that you don't know who someone is morally when you are sharing a shovel in the sandbox. But at what point do you have to say enough is enough? Steve's friend doesn't believe in "one girlfriend," but also doesn't believe in sharing this information with the girls he is sleeping with. In one particular instance (before I knew the real him) I became friendly with one of his girlfriends only to find out from Steve that he had slept with at least 10 other women while dating her. I was devastated. I wanted nothing to do with him especially if I was becoming friendly with those he was hurting. This friend also slept with a good friend of mine and I had the horrible task of sitting her down and gently telling her that he wasn't going to call her back.

Not only is he a habitual cheater, he has tried to influence Steve to be the same way. Whenever Steve is around him, he is not the Steve I know -- the Steve who says he will be home later and actually comes home later, not the next day. Steve even missed a birthday dinner from my family with cake and presents because he was out with this friend and the friend was driving and didn't feel like coming home yet. Steve admits he was wrong in many of the incidents but they don’t change.
I know I can't ask Steve to stop being friends with this person, but this is really affecting our relationship. It makes me question Steve's faithfulness. Steve and I have had many talks about this friend, and he has agreed that this friend isn't doing the right thing and is hurting the feelings of many women/people, but he doesn't do anything about it. I recognize that as much as I am mad at this friend, Steve is not innocent, but I don't know what to do since talking with him is not working.

– Annoyed in the city

Most of the time, AITC, I tell people that they should be able to survive their partner's horrible friends. I advise them to respect their partner's histories with these people and to simply avoid social outings with the undesirables whenever possible.

But in your case, I'm on your side. Big time.

It's fine if your boyfriend's friend wants to be a villainous cheater, but he's not allowed to mistreat your friends. It is a major party foul to mess with your best friend's girlfriend’s friends. Really, it's inexcusable.

Your boyfriend's behavior is also inexcusable. He goes out with this guy and doesn't return until the next day? And he missed your family event because of this he was running around with this idiot? Bad, bad, bad.

Usually, when we outgrow our childish, misbehaving friends, we learn to minimize them. We take them out for their birthdays, we roll our eyes when we go to their parties, and we try to focus on nostalgia when it becomes clear that their priorities no longer match our own.

But Steve's relationship with his friend is not about nostalgia. He actually likes hanging out with this guy.

You have every right to make demands. Steve doesn't have to cut this guy out of his life, but he does have to minimize him and set boundaries. You shouldn't have to hang out with the bad friend. You shouldn't have to sit up worrying when Steve is out with this guy. There are consequences to Steve's actions and "He made me do it!" isn't an acceptable excuse. It's ruining your relationship. You're allowed to hold him accountable.

If he has no interest in minimizing this friend and following rules that keep you comfortable, it's a red flag. Don't ignore it. He has to choose.

Readers? Is she allowed to ask the boyfriend to dump his friend? What does it mean that the friend has such influence? Is there cause for concern about cheating? Anyone had a significant other with a bad influence? Talk.

– Meredith