Nonono, OP is saying that he has digi TV, 2 cable modems in the same home, one that is his and one that's his other half's (both being paid for) and a couple of TVs that are running straight off the cable MATV style.
No theft of service involved, just some 'interesting' internal wiring.
Anyway onto the issue in hand, what you need to make this work reasonably is a nice 4 port splitter a la
http://www.hometech.com/video/splitters.html. Use 3 of the ports to service the 2 cable modems and the digibox, split the remaining port again and use it to service the 2 TVs.
That's a guesstimate on my part as I've no idea how much the tech who did the installtion juiced your signal, but that should work quite satisfactorily, and will replace the quite titanic multiple splitter loss you have now with a single 7dB kicking for the digital stuff and 11dB for the analogue.