Tom and Gina live in relation. They are not married.

[tufguy]

Tom and Gina live in relation. They are not married.


Please check my sentence.

 

[emsr2d2]

Tom and Gina live in relation together. They are not married.

Please check my sentences.

See above. In this context, "in relation" means nothing. The two of them are "in a relationship" (or at least I assume they are even though two people can live together without being a couple).

In what real-life situation have you recently needed to say those two sentences?