There are so many different ways to be a bad boy, and it’s not necessary to have a character hit abusive highlights in order to have the appeal.  Try including or focusing on some of the following traits:

The tough-guy look is an obvious note to hit, and there’s no denying that there’s a certain appeal to tattoos and leather.  But there’s varieties in that, as well.  He doesn’t have to dress like a biker; a pair of well-worn jeans or a penchant for brazen belt buckles can do the job just as well.  A general rule of thumb: be more casual and/or blue collar than convention calls for.

Brawling is always a fun hobby for the bad-boy, but don’t get sucked into the idea that it has to be angsty and cruel.  Some people genuinely like to fight.  Those people can find other people who genuinely like to fight and merrily give each other black eyes all night long.  And, of course, there’s shades of brutality between the two extremes.  A guy can go looking for fights without needing to insult someone’s recently-departed mother just for shits and giggles.

Being unapologetic does not mean the same thing as being a jerk.  (One is directed at self – “I’m not affected by your concerns” –  and the second is directed at others – “I’m going to be mean to you so you think I don’t care, even though I obviously do or why would I feel the need to be mean.”)  Everyone makes mistakes, and a bad boy can wear his mistakes proudly without having to go out and look for new ones.  Or he can make mistakes that don’t involve telling women to stay home and stop being such sluts.

Rebelling without a cause is a classic, if irritating, trait that rarely elicits cries of domestic abuse.  Buck authority!  The Man can’t tell me what to do!  I’ll sit backwards in my chair and skip class and answer the door pantsless and scoff at teachers!

Rebelling with a cause is a less-used, but much more defining, trait.  The bad boy doesn’t have to be good at rebelling, so instead of making calm and well-reasoned arguments against standardized testing, he could still just nail his paper to the wall with a pencil and walk out.  And then, of course, mope his real reasons to his oh-so-sensitive love interest later.

Engaging in dangerous hobbies, or possibly just manly/dirty hobbies, does much to add some bad-boy flavor.  Extra points if it’s a non-team hobby and/or not regulated.  Bad boys don’t play by the rules, after all.

Being unapologetic about his flaws can make him very awkward or unwilling to play along when he does care about someone, but the appeal comes from watching him work through the fact that he suddenly cares what this love interest person thinks.  Someone unused to caring may find themselves out of practice when it comes to empathy, but that doesn’t mean they scrape the bottom of the barrel before trying.

The basic thing to remember is this: Bad Boys don’t follow convention.  They march to the beat of their own drums, and they usually do it while being extra testosterone-y and broody.  Anything that defies authority or social convention while not giving a rat’s ass what people think, that’s bad boy.

But that doesn’t mean that a bad boy has to defy all conventions.  There are a few jerkish qualities that can be skipped entirely without the character having to hang up his leather jacket in shame.  Cutting out these traits will keep him off the “abuser checklist” and still keep the swoon.

Being controlling or possessive.  If the bad boy doesn’t follow rules, why does he expect other people to listen to him?  Let them do what they do!  He’s capable of understanding and respecting that, seeing as he does it himself.

Being sexist.  In fact, given our current culture, being unsexist would defy convention, don’t you think?

Being sexually aggressive.  Assertive, okay.  Confident, more power to him.  Active, all’s fine.  But aggressive?  Back off when the lady says no.  Or if that would end the book to soon, at least find a different method of getting them together.

Being physically abusive.  I’ll grant that if the bad boy has a terrible background and generally uses brawls and bare-knuckle fights to let out his aggression, this one might be hard to deal with.  Someone in that lifestyle could find it very difficult to suddenly shift gears and use a different anger coping method just because the person in front of them happens to be their one true love.  (Which is why “hitting inanimate objects to ‘let out’ your anger” is actually very bad advice.)  So this might be an issue that an author wants to work with.  But it doesn’t have to be on the bad-boy checklist, and it should only appear in places that actually want to work with it, not cover it up with the Power of Love.  (Any time I see emotions “fix” a problem like this, I just assume it’ll come back a few years after the final page, if not sooner.  Since that’s how this sort of thing usually works.)

Dismissing the love interest’s ideas.  A bad boy defies convention, not every single person he’s ever laid eyes on.  He can respect people’s ideas, even if it is just the few people who are “worth it.”

Deciding he knows better than the love interest.  Controlling the lover interest’s actions, movement, or other relationships indicates that he thinks he knows what’s best for her, regardless of what she thinks.  It’s not required that he thinks his love interest isn’t just as independent and capable as he is.  This idea can be entirely left out without challenging his bad boy image in the slightest.