ual taboo?

Ok...there's no real easy way to ask this so i'm going to give some quick background information. I've been with my partner (who's nearly a decade older than me) for almost 3 years now (i'll be 20 in two weeks, YAY!). We waited two years before we had and, not gonna lie, it's been great. We've been very safe and i know we are both clean and monogamous. I suppose my question is...is there ever a point where it's ok to NOT be safe? especially with a clean, monogamous partner....? I was just curious if anyone knew or could give some helpful advice...