I admit quite openly, that I do not know how K&I feel.
I can only judge by what I see them do and the interactions between themselves and others.
Indira and kostja are young and possibly confused with the current situation,They have to considers the income involved in their relationship, as well as their feelings.
In the end, Her vagina is her property and she is the only one to decide who can use it!
I want them to be happy and safe, if that includes sex with others, so be it, But that is their choice, not ours!