Been there, done that, have the T-shirt
Yes, gas during sex is horrible and quite embarrasing (even with my hubby that I have been with for 16 years)
Have you tried the different suggestions for gas such as beano, gas-X, peppermint tea, charcoal tablets? You may have to experiment with different things. I'm sorry that you have to go through it, hopefully you can find relief soon. I also would avoid certain positions that would tend to put pressure on your abdomen.