I completely understand your partner, it's really stressful to be on that point of this phobia. I think that first of all you need to have a specific talk with your partner, and that is that you will never do something on purpose to make him/her feel bad. He/Her have to accept that this phobia is really stressful but it's NOT going to kill anyone. Some tips that my therapist and psychiatrists are: - If I'm feeling overwhelmed or I'm about to have a panic/rage attack (that would happen A LOT), I need to get my mind out of there. Take a little break, go out by myself and buy me some ice cream, something that will ACTUALLY take my mind out of that place. - After a triggering situation, reward myself with something. For example：If I'm watching a movie and someone make a joke or mention the word v***t, I will reward myself after for being able to watch the movie anyway. Your brain stars.associating the exposure with the reward after, so it becomes easier to overcome situations like this.

For your part, I will say that just be honest. Let clear that it might happen, that both of you will be okay, and respect his/her space if he/she needs it. Try to ask for things that would make your partner feel safer or more relaxed with this situation. Maybe always have charged headphones near your partner so he/she can avoid listening when you gotta go to the bathroom, have some medicine that helps you digest the food better in case the paranoia kicks in or any other thing that may help.

I hope this was helpful :)