That's just it, Morality needs to be based in Compassion, to be based in Truthfulness, in Generosity, that is all positive. That's how you want to look at it.
Why is it that we say, Morality means we don't steal? 'Don't' has the word not in it, right? This is what we are referring to as a "negative expression." What does it actually mean, though? It means that we allow everyone to keep what they've earned, to keep what they've been given, that we are going to allow everyone to have their levels of happiness without us interfering. So when you think of "not stealing," what is it in reverse? We are actually giving others the freedom to keep what they actually have or to keep their life the way it is, their world the way it is.
Don't lie? What does that mean? Ok, here it is on the "positive side," we are being truthful, we are being truthful because we want to give people the truth. We don't want to give them a false representation of the world. We don't want to give ignorance to other people. So we give them the truth, that's the same as not lying. So with each one of the general guidelines of Morality (Buddhism has the five Precepts, the Judeo/Christian world has their Ten Commandments), if we look at them from a different angle we get a very positive feeling based in Compassion for other living beings.
Don't have an adulterous affair. What's it for? So we don't get caught up in our greed. Don't get caught up in wanting, wanting, don't get caught in it. The other way we can look at this is that we are allowing other people to live their lives with less fear, less greed themselves. We are allowing other families to stay as a family unit. We are giving their children something, we are giving, giving, giving, by not having an adulterous affair and these types of activities. When you are looking at the "Don'ts" or "No, shall nots," just turn them around, take a look for yourself what are you actually giving at the same time.