cheat on

Hello, please, my question is about the use of the phrasal " cheat on", whether its use is only restricted to members of a couple being unfaithful, or it has a broader use: for example, are the following sentences correct:

1. He cheated on his exam

2. Politicians are always claiming poor people cheat on their benefits

Thank you

Those sentences are fine. If you say "cheated on" someone, that's when it has the connotation of sexual unfaithfulness.

Thank you so much!