can't have it both ways

can't have it both ways

Cannot have two contradictory things at once. I know you love ice cream, but you can't eat it every day and lose weight—you just can't have it both ways.
See also: both, have, way
Farlex Dictionary of Idioms.

can't have it both ways

COMMON
1. If you say that someone can't have it both ways, you mean that if they benefit from one good thing, there is another good thing they will not be able to benefit from. Countries cannot have it both ways: the cost of a cleaner environment may sometimes be fewer jobs in dirty industries. Note: You can also say that someone tries to have it both ways or wants to have it both ways. If you go into the big leagues, you've got to play by the rules of the game, but she's trying to have it both ways. Note: People sometimes say that someone has it both ways to say that they are successful in benefiting from two things. You can have it both ways. If you want company, hang around the pool area, and if you have had enough, head into the forest.
2. If you say that someone can't have it both ways, you mean that one thing they say or do shows that they are not sincere about another thing. Where's that patriotism when you've been sending all your money abroad? You can't have it both ways. Note: You can also say that someone tries to have it both ways or wants to have it both ways. He tries to have it both ways on international law, criticizing foreign governments who do not respect the law, but refusing to accept laws that damage his own country.
See also: both, have, way
Collins COBUILD Idioms Dictionary, 3rd ed.

you, etc. can’t have it ˈboth ways

you must choose between two things even though you would like both of them: You want an interesting job that pays well, and yet one where you don’t have many responsibilities. Well, you can’t have it both ways.
See also: both, have, way
Farlex Partner Idioms Dictionary
See also:
  • you, etc. can't have it both ways
  • you can run, but you can't hide
  • can't do anything with
  • can't do anything with (someone or something)
  • you can't run with the hare and hunt with the hounds
  • if you can't beat 'em
  • have (one's) bread buttered on both sides
  • have your bread buttered on both sides
  • yellow dog
  • get (someone or something) out of (one's) mind
References in periodicals archive
But we can't have it both ways. I hear from people who say, `I was like Brian when I was 29--it's realistic and should be celebrated.' And I also hear a common criticism, `I don't want my mom and the straight world knowing about this,' even from people currently living that life."
Is it good for gays?