Why are human relationships are impossible to sustain in 1984?

In
, the Party tries to control every aspect of the people's lives. Certain
allowances are made for the expression of human instincts that had proved impossible to suppress
(chapter VI). It is tacitly accepted that Party members will sometimes visit prostitutes;
although it is technically an offense punishable by five year sentence, in reality the
authorities largely look the other way.

"Promiscuity" between Party
members is an "unforgivable crime" and to, at first, unimaginable. The Party does not
want people to form loyalties to each other that might be uncontrollable. Moreover, the Party
wanted sex to be pleasureless. Even between a married couple, "eroticism...