[UserNameGoesHere]

I'd say it depends on how the boundaries are defined for the particular relationship in question. Each person in a relationship will agree to what is or is not allowed within their particular relationship. If both people have different views as to what is or is not allowed, then they didn't communicate very well and the relationship is doomed anyway.

So one relationship may have very strict rules while another is very lenient. As long as one is within the rules of the relationship, it isn't cheating. Just make sure you define what those rules are beforehand.

It's best to find someone who has similar ideas to you as to what constitutes a relationship (what is allowed/etc...) but as long as both people agree to what is or isn't allowed and stick with it, there's no cheating. If there's confusion as to the rules and one person does what they think is allowed but the other considers it cheating, that's not cheating either -- that's just bad communication and fails the relationship though.