I've known police couples that make it and those that don't.
Like all relationships, the success factor depends largly on the individuals involved.
"Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety."
Benjamin Franklin, 1755
"Living in our society is like living in a very tall building. The rich live on the top floors. The poor live on the lowest floors. And only the cops travel to all the floors. Only the cops see it all."
Det. Ted O'Conner - Chicago P.D