Remember Clinton? One of the reasons conservatives loathed him was his disgusting immorality. Gross immorality in ones' private life seeps into the rest of one's life. Doesn't mean everyone who is flatly immoral is unfit for everything. There are degrees of immorality, and some positions are more sensitive or carry more weight than others.
Not all moral failings or character flaws are equal. The understanding that serious moral turpitude renders someone unfit for public service or a position that requres security clearances or other types of heavy responsibilities used to be common cultural understanding.
I am not passing particular judgement one way or the other regarding Santorum and his aide. We are not privy to the particulars. I have other reasons I do not love Santorum, although I like some things about him.
I don't feel strongly about Santorum either way. This incident does not move me, either, probably because I can't believe there is any other way to handle it.
I voted for him twice and will vote for him again because he votes for what I believe by and large. I don't expect to agree with any politician all the time, I guess.
I do think that all the sins I outlined are equal. Someone who has sex outside of marriage is no worse or better than someone who harbors hate or who abuses their body with food or alcohol. I can't understand why the sexual sins seem to rile folks up more.