We've had a lot of people here on Cheat Confession (CheatConfession.com) ponder this age old question. Here are my thoughts. Generally speaking, and I am not in your relationship or in your bedroom, "taking a break" means splitting up with the hopes of reuniting should both parties be inclined to do so in the near or far-off future. The romantic relationship would be thought to resume once both parties enjoy some time apart to soul search and to find themselves without the burden of a relationship. It's all about distance = perspective. Where that greater perspective leads the both of you is yet untold. In other words, it means you are single; at least temporarily.
That being said, your commitment to one another is on hold, perhaps just for the time being, perhaps indefinitely. If you are on hiatus from one another you should be free to explore what the single life has to offer, and to really take some much-needed time apart to figure out if you want to continue on your journey together, or if you want to keep on trucking solo.
If a relationship has issues that just don't seem to be getting resolved through constant efforts at communication, and both people feel like they are hitting a wall, then sometimes time and space is the best gift that you can give to one another. As you selflessly give that gift to your partner, you can also give yourself the gift of sewing some oats and exploring what the world has to offer, and yes, that includes sex.
Cheating, by definition, is one person in a relationship betraying the commitment and understanding of trust that both partners have agreed upon. If the understanding has changed or amended in some way, then it is not fair to label the actions of the other as "cheating." The trick is defining what that break means to each of you and being extremely specific about it (verbally, not in your head). One exception to this rule might be if both people decide they are taking some breathing space from the relationship, though they agree to remain sexually celibate during this time, until both people come to a decision about the status of the relationship. As cliché as this sounds, doesn't this all come down to communication?
If you suggest a break from your significant other so you can go find someone who will do something in bed that your bf/gf/wife/husband/whatever would never do, and you are just going on temporary "leave" in order to legally cheat, those antics are questionable my friend. It's not the army. There are no day passes. That is cheating, not because you are having those urges, it is because you aren't sharing them with your partner, but seeking your satisfaction elsewhere under the guise of needing a temporary break to sort things out.