Legal Question in Civil Litigation in California

Perhaps... If someone relied to their detriment (ie gave up work or moved to a new location to fulfill the obligation of companionship) the promise may be enforceable under the theory of promissory estoppel. Caution the theory is equitable and requires you acted in good faith and its all about reliance on The promise and what you did or did not do because you had to fulfill the promise.

Certainly not if the companionship involves sexual relations. Such a relationship would be considered "meretricious" and would be unenforceable pursuant to public policy and the criminal laws of this state.

I will add that contracts can be broken.... Lifetime unbreakable contract even if enforceable would be unrealistic to hold a party to