Our relationship goes through cycles.
When it is available, it is smoked and enjoyed.
We get along well, laugh more, are sometimes more affectionate and other times more content to just be.
When it's not available, we're not devastated.
Still laugh, still enjoy each other and still find ways to be affectionate, sexual and imaginative. I'll admit that pot enhances some of the stress-relief that we seek and it certainly brings a different and spectacular mood to our sex life. But neither of us gets "lazy". We both tend to talk more and express ourselves. I consider us "smokers" not "stoners". Though, I'll admit that the ceiling fan can be a fascinating object to observe sometimes.
From my experience, if there is an inherent tendency towards laziness or procrastination... pot is going to multiply it times a billion unless there are active steps taken to kick themselves in the ass. But, I also am friends with some highly intelligent people who smoke regularly and have healthy relationships. I think that sometimes it depends on the person's personality when sober.