Mirena IUD

So I’m getting the Mirena IUD put in here shortly and was wondering what people thought about it? My SO is dying to know if we can stop wearing condoms and if he’d be able to finish inside me without too much worry (obviously anytime you have sex there is the risk for pregnancy). Also any other general things about the IUD itself. My OB told me I wouldn’t be getting my period for the 5 years it’ll be in.