Why...?

Why are so many girls uncomfortable farting around their SO? Like, one of my good friends has been with her boyfriend for 3 years and she was like "I accidentally farted around him once, it was so embarrassing." Another one of my friends even went as far as to say that she wouldn't even fart around her friends. Why? What's wrong with it? If your SO doesn't know that you fart and/or isn't okay with it, then that's a problem with them, not you. My boyfriend and I only see each other a few times a year and when he stays with me I fart whenever I have to, and so does he. I don't leave the house, I don't go in another room, I don't hold it in. I just don't see a problem with it.