Someone please tell me how this happened

Just prior to trial of my case, my attorney informed me the judge was not going to allow the issue of adultery on the part of my ex-spouse to be admissible in Court. He stated that the judge was aware of the allegations (it was admitted during the custody evaluation and at other times, to my 17 year old son, to me, etc.), but was only going to focus on the financial issues. I requested my attorney to file an objection to this being inadmissible (to preserve it for appeal), but he did not do so. During the trial of the matter, the issue was “alluded to” and the attorneys approached the bench. Opposing attorney stated to the judge, “WE agreed this issue was not going to be presented.” There was no judicial notice taken–not to my knowledge. I thought an attorney HAD to present evidence if the client so wished. HOW could this have happened? Did my attorney AGREE to this issue not being presented? Could he do that? Is that the only way? I’m just searching for answers and any help would be appreciated. Thanks.