No, We Can't Send Your Ex the Bill

Legal fees are a concern for all clients and of course a long, contested divorce or separation can become expensive. 

What seems to upset clients most is when their estranged partner seems to be the one driving up the fees. Initiating court proceedings over petty matters, frequents letters and calls, demands for repeated changes to documents, unwillingness to compromise, settlement meetings that turn into arguments.

So the request from the client is sometimes, "I want my ex to pay your bill". 

While that's an understandable request, it's not something the lawyer can make happen. 

First, it is unethical for the lawyer to contact another lawyer's client directly. For this reason alone, sending bills to the other side would be unethical. 

Second, our client is the one with the contract with us. They called us, asked to hire us and agreed upon terms of payment.  We do not have a contract with the other client. A professional cannot send a bill unsolicited to someone who has not agreed to retain us.

At the end of a court hearing, one litigant can ask the Judge to award "court costs". This is a payment from one litigant to the other, most often awarded to a successful litigant. The unsuccessful client would have to pay the successful client, in theory because the successful client should not have had to spend the money on legal fees for an unnecessary court hearing.

But this has nothing to do with the contract between the lawyers and their clients. It does not create a new contract between their lawyer and their ex. If you hired your lawyer, you have to pay him or her and then hopefully also collect your court costs award.