Directional Coupling at kHz Frequencies
Look up "Power dividers and directional couplers" in Wikipedia and go down to the section on "Cross-connected transformers".  These form a directional coupler that can be tailored to any degree of coupling.  Select transformers whose bandwidth spans 10 kHz to 100 kHz at your impedance level of interest, and are sufficient to handle the voltage and current, and you should be in business.

On the web, you can find a number of other references to the same thing, usually used at rf frequencies, but the info is adaptable to your case by appropriate selection of transformer bandwidth.

Remember that the terms "forward and reverse power" only have meaning when referring to a transmission line of a given impedance, assuming you are talking about the average power flow over many cycles.