Hi and welcome to JA. I am Ray and will be the expert helping you today.
Here it is in both your names.You have a half interest here by marriage.The other half is there was no right of survivorhsip passes under the laws of intestacy.
Here if this was bought premarriage his share is separate property not community...
In your case since there is one child you get your half, half of his half so 3/4 total and 1/4 to the single child..
Laws of intestacy..
You will have to buy out the 1/4 interest unless the child will quit claim it to you during probate
The problem is you bought house as s single people if you were married you would take all community under intestacy laws above.
You may want to consider a lawyer here to apply for probate and handle buying out the share or maybe child signs it over to you .
But you have to account for his 1/4 share in probate here.I wish I could tell you the law.But him not having a will punishes you under California law since it was premarital purchase.
I appreciate the chance to help you today.Please let me know if you have more follow up.I know this can all be kind of overwhelming.
You can locate a lawyer here through the state bar..