Question Regarding LAN connection and a game in progress

So I have been working away at my game for a very long time and my flat mate has been watching from a distance and he is becoming more and more interested, after I told him I think it is possible to play a networked game so we were in the same league he decided he wanted to buy it.

So, the plan is to connect the computers via lan cable and play a game over the network. But, is it possible for him to slot into my game as a manager in the EPL? So I can just continue my game as normal? Also, how does the network work? Do we both need to be playing at the same time to keep the calender rolling or is it sort of a turn based system? I ask because if it requires both of us to be playing at the same time Ill just make a new game and keep my original one separate for when he busy.