Prohibited Relationships

A few years before I was born, my mother had an adulterous affair and got pregnant. My father knew about it and was angry at first, but then he forgave my mother and remained married to her and raised my brother as his own child. My parents kept secret from us for many years that this happened and hid the fact that my older brother is not my full brother. Only after my brother and I grew up did we learn the truth. Presumably a child born from adultery is a mamzer, which would make my brother a mamzer. But I also understand that once a woman has been unfaithful to her husband, she is forbidden to him and they must divorce. Well, my parents did not divorce and have married to each other for almost forty years. My question is, since my mother was already forbidden to my father at the time of my conception, and he knew that but remained in his marriage to her, does that make me a mamzer?

So rabbi, some feminists says the Torah prohibits adultery. But all females must have the right to do adultery. Moreover those females who commit adultery never confess that they committed adultery. Now, does what the oral law of Judaism say about adultery?

Do you think that the collaboration between Islam, Christianity, and Judaism can prevent adultery from happening anymore? If so, please explain how.

Shalom aleichem Rabbi Lauffer. Thank you for answering my last question. In "Thursday Nights with Rabbi Avigdor Miller Vol. 1" on page 166 Rabbi Miller says "I know a case, in Williamsburg, where a woman made a very big mistake going to a chiropractor. He was somewhat free with her, but she said to the rabbonim nothing happened. The rabbonim discovered that there was something that would seem nothing to her, but in the halacha it was more than nothing. It was something serious. She had to take a divorce from her husband...It's a tragedy, but it can't be helped. But once she committed adultery, it was over-and adultery doesn't mean what you think adultery means, even if it may seem quite innocent. It's the same as adultery." What, besides actual intercourse, constitutes adultery according to the halacha? Thanks a lot.

As always thank you for taking the time to answer questions. If its true that during the Roman occupation of Israel that they weren't allowed to put to death. Do we know what sentence was substituted for "stoning" in the case of adultery?