Sex with Mirena

I just recently got Mirena and I've been a little reluctant to have sex with my SO the whole point in getting it was so we didn't have to worry about pregnancy scares but now that I have it I'm just scared the idea of him cumming inside of me is kind of terrifying even though I know nothing will happen pregnancy wise it's a bit scary for me... I just wanted to know if anyone else had this feeling after receiving a Mirena.