Is it unethical or against a legal code for her divorce attorney to advocate against reconciling our marriage?

Your question requires far more information about the total circumstances before any kind of ethics opinion could be provided. The important part of that statement is the word "opinion". There is no clearly applicable "rule" that would answer your question and any answer is likely only to be one person's opinion. You could ask three different "experts" and potentially get three different answers. No competent lawyer considers it his/her responsibility to "advocate" what the client does or does not do, but there is clearly nothing wrong with your wife's attorney giving her his opinion about you or about what she should do. That opinion is likely based partly on the behavior you have demonstrated and partly on the attorney's experience in similar situations. So, even if someone else might have a different opinion, that doesn't mean either one is right. Unless there were some reason to believe that the attorney is influencing your wife with knowingly false information for some personal benefit, what he tells you wife is simply between him and her. She is paying for his opinion and it is up to her to decide whether she accepts it and what she does based on his opinion. Simply stated, an attorney has no legal or ethical duty to encourage or discourage reconciliation in a divorce case. Similarly, few attorney have, or think they have, the ability to do anything more than express an opinion about the likely success or failure of any attempt at reconciliation. Most divorce attorneys, in my experience, won't even start a divorce case until the clients affirmatively indicates he/she has decided that divorce is necessary. So, a lawyer's opinion about reconciliation are usually about whether to make a second (or third, or more) chance effort to try again something that has already failed at least once.

I do not believe this behavior is against a legal code. As far as being unethical, it is borderline and would depend on other factors. You should speak to an attorney about the specifics to see.

No, Its not unethical. She is paying him money for his opinion. The fact that she has already gone to an Attorney is bad. I always recommend A Priest, Rabbi, or Pastor as well as Marriage Counselors, Psychologists, etc. as a first option. But you do not know if they discussed those issues or not because of the attorney client relationship.