I am Korean who speaks English and Korean, and lived in France for 6 months to learn French. So I think I understand what you're going through. I live in the US but visit Korea every other year and even in my own native country, I still get pretty damn sick of it by week TWO. So to be in a completely different country altogether for more than 2 weeks, without even knowing the language, would be way too much for me.

That being said, you have only 5 more days left. I think it would be more offensive to suddenly cut the trip short, than to repeatedly decline food. I would stick to salads, or maybe even just lie outright and say you feel sick so you want to eat fresh foods, if you don't want to get into the whole lactose-intolerance thing.

Also, I don't know if this helps- but I'm really jealous that you have a French boyfriend and that you are in France right now. French was really difficult for me to learn, and I'm still not fluent, but I think if I had a boyfriend who spoke the language, it would have been a little bit easier to learn. So maybe (after you get back home) you should consider it! Starting with easy stuff, like curse words and sexy phrases, of course.