1) But would a later hookup with Miss Grundy make the sin retroactive? See what happens when we get so legalistic about sin? 

2) On derivatives, who performs the inferring rigor I admit should be part of the discernment process? You can't believe how some priests have told me I should interpret the Bible about marriage--180 degrees away from what 40 years of on-site learning has led me to infer. The most misunderstood word by clergy is "lust." I say misunderstood, because they all can't be wrong...or right. It ranges from harmless fantasy to "strategic intent" to sexist objectification to unhealthy preoccupation to demanding behavior to imposed relations to "just ask me if you have questions" to "I really don't know; you're the  one who knows far more about these things than I do."  

3) Is the absence of trust in fellow Catholics a derivative sin from some commandment? Please tell me it is; I have some sinners I need to admonish.
 
4) Your mom and dad sound just like mine.