You have no rights in California other than possibly Marvin rights. You will need to have a consultation with an attorney who is familiar with the requirements of a Marvin case.
Michael Schwerin, San Jose, California phone: 408-295-4232 email: email@example.com. Consultation fees, rates and retainers vary based on need and ability to pay.
Your posting is unclear. If you are married to someone else, you are married to someone else. Califonria does not have common law marriage (and if you were married to someone else ... )
The "Marvin" rights described by my colleague are essentially "contract" based rights so unless you have an agreement, no.
The above is general legal and business analysis. It is not "legal advice" but analysis, and different lawyers may analyse this matter differently, especially if there are additional facts not reflected in the question. I am not your attorney until retained by a written retainer agreement signed by both of us. I am only licensed in California. See also avvo.com terms and conditions item 9, incorporated as if it was reprinted here.
Sorry, but no.
1. You're still married to someone else, so you CAN'T get married (in any way) to your boyfriend, or become registered domestic partners with him.
2. There's no common-law marriage in California, so even if you WEREN'T still married to someone else, simply living with someone in the state of California doesn't ever make you married.
3. Unless you're married to, or domestic partners with, your boyfriend, you're not entitled to any of his pension.