Personally for our family, dessert is off limits in restaurants (wheat, rye, barley, egg, peanuts and bananas). We have a few places we go for desserts such as Burger King, Rita's and depending on the child, McDonald's. But in your average every day restaurant, desserts are verboten.
Potlucks and dinner parties - unless the person in charge is totally aware of our allergies and what it takes to keep us safe, we take our own food. My kids could honestly care less and most have been understanding about it (or at least had the good sense to eye roll in private, kwim). The kids are used to taking their desserts to birthday parties to eat instead of what is served, this is just a broader extension of that.
Restaurants - I do have a looser comfort zone than others but at the same time, we have the "talk" and we are prepared to go if we feel that they cannot serve us safely. That is not to say that we haven't had some pitfalls over the years. For my oldest who is allergic to wheat, rye, barley and egg, breakfast out is a nightmare. We had a trip a few years ago that involved two reactions in places that swore they could confidently serve him. At the same time, we did discover a place that could. We also had a reaction at Outback because the manager shared a certain dressing would be safe, he reacted and she said well it just has three ingredients - honey, mustard and mayo. Ummm, those are not just three ingredients. FWIW, I did ask to see an allergy chart and or ingredient list and instead she came out to say this dressing was free of egg after asking the chef.
I will say that we have a small list of restaurants that we can eat out together as a family and when we do find them, we eat out there like it's no one's business. Some people prefer chains with clear allergy menus, some people prefer local businesses where they can establish a rapport with the staff. We do a mix of both because we want the options for when we travel.
There are sites such as Allergy Eats that have reviews of restaurants locally as well as nationally. I tend to work off that if I am looking for a specific kind of restaurant or traveling. And since we have kids, we do tend to frequent way more fast food than I care to.
The hardest part of this journey is that I have to be verbally outspoken to people I love and people that I don't know. Very hard for this shy girl. But at the same time, we are talking about life or death situations.
And honestly, I know OCD has probably been a struggle for you but in some ways it may help to keep you safe. Am I saying you should go all out and let it control your life, no. But that checking and rechecking may save your life.