I actually DO care what politicians do in their personal life if they lie about it. Pretty much by definition an affair is going to involve lying. If a pol is into goat felching, hey whatever as long as it is legal and they are open about it. However, chasing every skirt in sight while being married and lying about it shows a distinct lack of character. Unless, of course, the pol has an open marriage and is honest about it (like any pol would ever admit that… )
The people we elect should be honest. And smart. Having an affair is dishonest and dumb.
My theory is that any politician caught lying about anything* should be run out of office. The problem, however, is that voters tend to ignore this kind of behavior if ‘their’ guy does it. The other side has a field day if someone in the opposition is caught doing this kind of crap yet we all know that a large portion of politicians on both sides of the aisle are full on lying bastards.
Caught in an affair? Kick 'em out. Caught cheating on taxes? Throw 'em out. Caught doing dirty business deals? Toss the bastard out.
*Of course, this can get tricky for a pol who honestly changes their opinion on an issue. But they should be able to justify their change of heart.