TMI super embarrassing! My boyfriend farted while I was giving him a blow job!?

I was so grossed out I almost puked, this happened 3 months ago and he was sorry he didn't he said he couldn't help it. Now he wants me to do it again he said 3 months is along time without a bj. I just don't think I could get myself to do it how do I get myself to trust he won't fart? He goes down on me pretty much everytine we do it. And he said he would like if I would return the favor. But I'm scared of it now! 💩💨🙊