This is quite hard to explain, as it is idiomatic in British English, but doesn't really have a single meaning. It can also be used slightly differently in different contexts and in different regions of the UK.
In this particular context, it shares at least some of the meaning of the similar expressions:
- "There you go"
- "There you have it"
- "That's how it is"
In the context of your example, "there you are" is being used to express the fact that the speaker cannot change the situation he has just described and has resigned himself to accept it. He appears to have some odd habits, and as a consequence, his wife thinks he is "mad", and he accepts that he cannot do anything to change her perception.