An elegy for Dylan Thomas

'With rum tourists, inspect his grave' —> suggests the person who's grave it is was famous

'Death was his voluntary marriage' —> death is the only thing he is now committed to. 

'Poor silence sold to that rich and famous bride' —> sounds like his widow sold his story to the press for money, that he worked so hard to keep private. 

'Not even for the sake of love' —> Dylan Thomas was loved by everyone but all of their love cannot bring him back to life.