I felt kk was referring some time in past he messed up and lost everything.. and he isn't able to be the same person as before cos of that. May be he is extra careful...
Honestly speaking after seeing kk in bb I feel he's a delicate darling ... Very hard to be in a relationship with such people. They weight of that relationship would totally be on a single person.
Karan has told Teja that he has been in relationships with older women only earlier coz he wanted the feel of being taking care off but now he wants to change things in life & settle for a younger partner as he wants kids
In earlier days convo with Shamz he had admitted that in his last relationship he wud go on shoots to avoid fights & facing the problems which wud frustrate Anusha a lot
So in short yes he's sensitive & definitely needs a person with lots of patience & understanding. He needs a female version of Nishant to be happy in life