> seems like a major relationship booster

Not in my experience. Drugs of any kind usually cause your partner to feel too distant from the "real you". Drug use may also indicate a lack of confidence and inability to handle mundane situations.

Being an unreliable partner has to be one of the top relationship killers regardless of drug use.

> kinder to people as well as letting go of small petty things

I may be misunderstanding what you're saying here, but relationships should be way deeper than just being kind to each other. Disagreements are only as bad as the way they're handled. They need to be worked out early or the disappointment and irritation will only get worse. Burying your head in the sand doesn't sound like a good strategy.