“Religious reasons they can shack up but can’t /won’t marry? Not buying it.”
They could say they are of different Religous faiths and it would cause family problems to marry. The point is, they could use BS reasons just like the queers will.
Bottom line...Benefits for sex partners.
The military used to make it difficult for you to get married. It is much easier to house single GIs than GIs and their family members. There were a bunch of policies we always thought was strange. One being that the lower ranking troopers did not get on base free housing and got less money in dependent allowances. This went back to the civil war days but no one really knew why.
There was also a rift between the barracks dwellers and their base housing counterparts. Same rank, but one gets a house and extra money and the other gets a roommate. I imagine this will create a lot of resentment in the ranks.