I've had a bit of an issue with my DH lately with this. He had a bug that upset his equilibrium slightly, and consequently he's been a fair bit windier of late and more frequent. So the farts themselves are not his "fault" and are not the issue. (Some may say its natural and never your "fault" but if you are being subjected to hangover farts or something then you could argue a lifestyle choice)
However, my patience is starting to wear a bit thin. I had the bug too so know what it does and it does go on and on but I've just got so sick of copping a lungful because he hasn't warned me. I understand if I "follow" him somewhere and corner him that its not his fault but if I'm in the kitchen and he wanders in, sits down, starts chatting, lets rip, says nothing and suddenly I'm in a cloud, well, that's not acceptable.
I also dont like hearing it - some effort to be silent is appreciated. It is possible to let them out silently with a bit of careful separation of butt cheeks effort.
So the other day I actually sat him down and raised it as an issue. I said I dont mind farts per se and think its good that we have a farting relationship, but that if he has a smelly one, it wouldn't hurt to leave the room, or at least warn me depending on who was there first etc.
He agreed, and apologised that he'd slipped a bit on the promise he made himself when we married (he promised himself on our wedding night that he'd treat me like a queen!)