Cumming inside

So my my boyfriend and I have been dating for a little over a year and we've always used protection. (I am 21 years old and my boyfriend is 25...just as some extra info). I have the Copper IUD as contraception but we use condoms as well just to be extra safe... Even though we are very concerned about getting pregnant, we would like trying to have sex once without a condom at least once. It's something I would like to do but I'm really scared at the same time, as this would be my first time without a condom. I know the IUD is one of the most effective forms of contraception, but nothing is perfect. Any thoughts?