I live in California and I have been renting a room from my ex-husband for over a year.?

I live in California and I have been renting a room from my ex-husband for over a year. Instead of giving me the court ordered $699.00 in child support, he accepted it as rent paid. I was giving him an additional $100.00 for my car insurance. This was to be a purely platonic tenant/renter relationship. After a year, I began a friendship with a co-worker. That is when my ex-husband served me with a 30 day notice to vacate. Over the next 30 days he continued accept the $699.00 and he also canceled my car insurance. I cannot afford to move in 30 days without the help of child support (our child is 12yrs old) so I have a wage ignment ordered against him. When he found this out he told me that if I am not out by the 1st of September, he will have the sheriff come out to remove me. Can he legally do that? What are my rights? By the way- he did not claim the rent on his taxes last year; can I use that to get him to give me another couple of months to afford moving costs?