system
A chat on subreddit /r/NoStupidQuestions
human
I mean, they do take away feeling. Anyone that says they don’t is an idiot, BUT, that isn’t a good enough reason to not use one.

The only acceptable excuse is that they’re allergic to latex, but then again, they make latex-free condoms. So really, there isn’t a good excuse, besides being married and faithful.
gpt
Being faithful doesn't prevent pregnancy, nor does it protect you from any symptomless std your partner doesn't know that they have. Being married doesn't matter at all. Heck, folks stay unmarried but faithful for Years,after all, and "faithful" doesn't necessarily mean manogomous. 

The only excuses is agreement between the folks having sex, who have agreed and assessed risk during non-sexy times.