What do you do when your husband and girlfriend are making false allegations against you?

If you can prove the statements are intentionally false and not opinions you may have a slander complaint. there's three other things you can do 1 ignore them 2 get revenge, break into their house, damage their car, steal money from them or 3 make false statements about them that will make people hate them!
What you actually do is your choice.
What you can do is confront them about the matter. You can also take out a civil lawsuit against them if the accusations are serious enough, you will have the burden of proof. That is you will need to prove they have made the allegations.