Dear Forlorn:
Your frustration with "United" is pretty understandable - but is he really that much worse than the other available uh, partners in MSN?
American, Delta, Northwest (who is pretty forlorn itself!) - all of these offer nothing but regional jets to/from MSN. Unless you are willing to make that drive to MKE or ORD, there won't be a lot of mainline flights from MSN for you.
If there were someone better close at hand, I'd say go for it and dump United - at least a "trial separation." But you would be ditching your partner for one who isn't a whole lot better, I think.