I think the context of chaste which is used with those who have a same-sex attraction is abstaining from sexual behaviors. Aside from the obvious physically sexual activities, I believe that an improper and unchaste behavior (i.e. a hug or kiss on the cheek, etc…) is largely subjective to the individual. In other words, what may “turn on” one person, may not another. If an individual actively participates or engages in behaviors that they suspect may lead to the narrow occasion of sin or produce a sexually gratifying end onto itself, I think that would be considered as being improper and unchaste.

Living a chaste life should be seen more as a process of a perfection and purification of the heart and soul than just a check list of do’s and don’ts; where one may initially carry their cross with the objective of avoiding sin, in time through perseverance and God’s graces, some may eventually embrace the cross they were given with a purified and selfless love for God because He is God.

I just re-read your question and wanted to add, if two individuals with same-sex attraction have an attraction towards each other, as difficult as it may be, it would probably be considered scandalous if they continued to have any type of relationship, and therefore should not continue to have any type relationship.

It is not improper for a hetero to hug and kiss and pat the back of someone of the opposite or same gender even if they are in a married state.

That’s not necessarily true, it all depends on the individual’s intentions and relationship with that person.

It is not improper for a hetero to hug and kiss and pat the back of someone of the opposite or same gender even if they are in a married state.

At what point does the action of ssa become improper and unchaste?