From what you say, if there is no neutral, and you have a two-wire system (no counting the protective earth connection), then you connect your a.c. adapter at 230 V line-line, and you measure the current in one line only (it does not matter which one, because the current in the other line is exactly the same current that you’ve already measured).
Therefore you connect your emonTx exactly as we do in the UK.
Remember to plug in your a.c. adapter the same way round each time. If you reverse it, you will read the real power as negative.
Then you must have a neutral connection - or a fault to earth. What is the voltage between lines and the voltage to earth (ground) of each line - is it as you wrote above, 110/115 V and 220/230 V?
Do you have some appliances - lights for example - that run at 115 V, and some - cookers, air conditioning - that run at 230 V? If yes, then it would appear that you have a split phase system, the same as North America.
That means you cannot use the a.c. adapter to power your emonTx. You must use a 5 V d.c. USB power supply that will give you a stable 5 V whatever the supply voltage is.
If all your appliances are 230 V, then they do not have a connection to ground (except a protective earth), therefore I cannot see why the current in the two lines is different, because there is nowhere else for the current to flow. Whatever current flows in on one line flows out on the other.
The only way the currents in the lines can be different is if there is a connection to somewhere else, and that must mean there is a fault either in an appliance or in your wiring.