It appears like he has some deep-rooted emotional issues which he hasn't addressed yet. Smoking drugs - is that a frequent occurrence? Is it social or do you feel like it is an escape? If is the latter, have you discussed or expressed your concerns with him? Maybe even urge him to seek help. Cannabis for the most part relaxes the user - there is a sense of calmness, fit of giggles, hunger pangs, sleepiness - so it is worrying that it brings out anger in him.
And to answer your question, no, love is almost always never enough. It is essential but there are many other factors which help to sustain a healthy relationship, factors which vary from person to person, for example trust, honesty, loyalty, commitment, mutual respect and good communication. If you feel your relationship is lacking any of these criteria then I believe you are being shortchanged.
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Love is like a merry-go-round: you get all dizzy, and then you feel sick!