How do Lord Henry’s comments on marriage support the novel’s motif of leading a double life?
Lord Henry Wooton is an influential character to Dorian Gray. He serves as an agent of change in Dorian by provoking him to explore every emotion and sensation that Dorian may be curious about (namely, sexually-based) and to indulge upon his weaknesses.
Along with the many aphorisms in the form of so-called advice that Wooton gives Gray, one of them is never to marry. According to Lord Henry's opinion:
Men marry because they are tired; women, because they are curious; both are disappointed.
This is enough proof to show that Lord Henry would be inclined to lead a double life since, to him, marriage does not constitute any form of sacred institution nor sentimental bond that must be respected or safeguarded.
Furthermore, Lord Henry seems to detest his wife, Victoria. It is almost as if Lord Henry has found out later in his life that he may very well be asexual or promiscuous either with the same sex or with the opposite sex. This is perhaps the explanation as to why he would choose to spend so little time with her, to openly lie to her, and to simply ignore her as a "decorative piece", which is his real opinion of women.
My dear boy, no woman is a genius. Women are a decorative sex. They never have anything to say, but they say it charmingly. Women represent the triumph of matter over mind, just as men represent the triumph of mind over morals.