Legal Question in Real Estate Law in California

It seems to me that there are two interrelated legal questions here: first, how would the law "divide" the equity in the house between the two of you; and next, how do you force the sale of the home and the distribution of the net proceeds?

In analyzing the amount (percentage) of the equity of ownership that "belongs" to each of two (or more) owners, a court can, and probably should, pay attention principally to the relative contributions made by each to the down-payment (purchase money). There is an old legal principle, once part of California's statutory scheme, written out of the law without express repeal several years ago, called "purchase-money resulting trust" which holds that contribution to the purchase money, and not percentage of title held of record, truly determines ownership.

It's unclear how much down-payment you paid at the time of purchase, but if I correctly interpret the given facts and she paid 10% down and 90% was financed, the woman would be awarded 100% ownership. The commitment to make half of the payments doesn't figure into the equity ownership computation under the purchase-money resulting trust theory. Also, the contributions you subsequently made to mortgage payments would probably be treated as equivalent to paying rent to a landlord.

(A resulting trust arises at the time of purchase, and unlike a constructive trust, is not a later-applied judicial remedy).

Factors which might prevent a court from finding a purchase-money resulting trust and thereby allowing the judge to find that you indeed have some equity in this home might include (a) an express or implied agreement for shared equity ownership at the time of the purchase; (b) an intention on the part of the woman to make a gift of some ownership (proof needed unless perhaps you were husband and wife); or (c) neither the judge nor the other party's attorney has ever heard of a purchase-money resulting trust.

If a court somehow gets by the purchase-money resulting trust principle and fails to apply it or chooses to ignore it, and finds that you do indeed have equity as a co-owner, then an action for partition would be appropriate. A partition action is one in which an unhappy co-owner of property sues for a court order that the property be sold and the net proceeds after costs of sale and paying off liens be divided equitably. Equitable division would first look at the percentage ownerships shown on the county record, then adjustments would be made for disproportionate expenditures made by one or the other of the former co-owners for expenses such as mortgage payments, property taxes, insurance, and necessary maintenance.

All in all, I'd suggest making an offer to quitclaim the property to her in exchange for (1) her getting you completely off-the-hook for the mortgage at her initiative, which could be done through an escrow which would also remove you as a co-owner, thus satisfying that problem, and (2) some pay-back to you, in cash, of what you've contributed in terms of mortgage principal and other payments. This part (2) cash could also be looked at as a "fairness" payment, or in lieu of what she'd have to pay a lawyer in costs and fees if the matter went to court for a partition action.

You could also proceed directly to filing for partition, but this could open a can of worms if she gets ahold of the purchase-money resulting trust idea, and could also cost you a lot in fees even if you won.