What makes you think he's keeping it quiet at the office? I for one let the good times roll to the tune of at least 7 times a day at work. The difference with work and home is that he can blame it on other people at work.
Add to the fact that people in public places like to pretend nothing is going on for fear of being blamed for the "phew", you can pretty much let 'er rip at work free and clear. Work is the optimal place to fart. My guess is you assume he's not doing it at work.
Now, why is he farting around you? Well he's probably a little too comfortable, or even worse, a little immature. My guess is he cracks up when he does it as well. Truly, it could be your fault. You've made a deal about him doing it around you and how much it bothers you, so he keeps doing it because it entertains him. Once again, immature.
If you want him to stop, I suggest you let them fly around him. Now he'll either get disgusted by it and stop so that you'll stop or you two will live in the nastiest smelling house on the block in which case I'd suggest you seek counseling and buy stock in air fresheners.
Wow what a bitch. i would dump her. maybe you shouldn't be allowed to sneeze or poop. and you have to do it at the same time and spray it at yourself in the mirror.