Self's the Man

In the setting of a lymeric, here used to convey the humerus  tone set within the poem, which is shown in the rhyme scheme, AB CD. 
The poem starts off with -Oh, no one can deny / That Arnold is less selfish than I”. The colloquial “oh” gives a sense of how he brushes it off, and he seems to be boastful of his selfishness. Into the next few lines, he presents a stereotypical image of marriage as entrapment, “married a woman to stop her getting away” and the ironic aside, ‘Now she’s there all day” as though his “less selfish” friend didn't know what he was letting himself into. Notice how he refers to her as a mere “woman” – not a lover, and there seems to be, at least from the persona’s perspective, no love in the relationship.
The hyperbolic language used to describe the 'stereotypical' marriage in the following stanzas, "he has no time at all" suggesting how  the marriage is so consuming,Arnold, has no time to himself, the metaphor of "it's put a screw in this wall" is somewhat what the marriage has done to him. He has been screwed to the wall of marriage, where time, alone, selfishness, cease not to exist, merely hanging around him but unreachable. Here we can get a sense of sympathy from the persona to Arnold, where he then goes onto comparing "his life and mine" makes the persona feel "a swine" (feeling like an unpleasant person", and the realization bestowed upon him that Arnold is "less selfish" than the persona. But continues to justify that marriage is selfish, that "not just pleasing his own friends" suggests that he is pleasing the one he loves, the woman he chose to marry, and surely that is not selfish to say the least. 
But in the final stanza, a conclusion made by the persona, that "he and I are the same" simply meaning that in oth their lives, they made the selfish decision to do what they wanted to get out of life. But the persona knows "what he can stand" meaning that a marriage, children and the commitments to that are not what he could manage.