PLEASE comment, I need outside perspective

So I just had the 5 year IUD, Mirena, put in a few days ago and part of the reason I got it was so my boyfriend could come inside me. I know that you should always use 2 types of birth control for 100% protection. We’ve always used condom and pullout. I feel insecure about letting him come in me because we’ve never done that before and it’s nerve racking because it’s new. We’ve been using the same method for 3 years. I want him to very badly, but I wanted some advice. If you had/have an IUD or know someone... is it safe to just go for it. I’m waiting 2 weeks just so my body can adjust to this foreign device, but after that would it be ok? I know this seems like a naive question considering birth control is partially made for protection against happy accidents... I guess I’m just looking for some reassurance/advice/guidance. PLEASE comment!