Legal Question in Family Law in California

You would have no rights. You were not married and you know the man is and has been married (impossible to be married to two people at a time). You cannot have an implied contract of marriage with you since bigamy (being married to two simultaneously) is illegal. Time to move on.

I'm not sure Mr. Schneider is right. I have never looked into the question of whether a Marvin v. Marvin type claim can be asserted by a woman who knows the man is married to someone else. There may actually be promissory estoppel or other quasi-contract claims that could be successful. You're not going to find any real answer here, however, because the question is so unique. You need to sit down and talk to an attorney about this in person.