What do you think of me going to conduct surveillance on my s.o. and his friend?
You've gotta be kidding. What would you like to know?
I want to find out if they're spreading rumors about me.
Why do you think they're spreading rumors? It's not good to spy on your friends.
I don't trust them and want to know if they are saying bad things about me.
I believe it's best to just not cause actual controversy by spying on them. They're your s.o., so they would definitely open up to you and talk to any problem that you may have. Communicating is key in relationships so it's necessary to continue it.