Hi Casabevron - I'm not surprised you're in a bit of a spin about it, it really is a huge thing to get your head round. My DS1 is 8 and anaphylactic to dairy (now doing desensitisation so we are slightly more relaxed but most restrictions still in place). He outgrew egg white allergy at age 2.
Like the others, I want to stress that all of this is a personal decision and there are a number of valid ways of dealing with it - some depends on your child's reactivity level and some on your own personality and coping strategies.
You don't say whether your DS is likely to have an anaphylactic reaction on contact, which I think is a key point. I always tried to keep DS1 away from skin contact but didn't have any evidence that it would cause a serious reaction.
We have gone through different phases with 'may contain' foods for DS1 himself, depending on his blood results and which specialist we were seeing at the time (we moved a couple of times so are now on number 3). The main problem with them seems to be that you can never know, and one batch may be fine but another one could be contaminated.
I am super-vigilant about utensils etc, and often go through several sharp knives when cooking or during a meal if I'm not 100% sure what they've been used for.
As for the rest of the family, we eat whatever we like really, though I would be careful if I was about to kiss him after drinking milk or eating cheese (but wouldn't worry about 'may contain' type products - again, I'm sure some people do need to on the basis of what their child reacts to, but we've never had a problem). I think your reaction to this may be a bit over the top, especially given that his reactions have only been to raw egg white, whereas the quantity of (no doubt cooked) egg white in a 'may contain' food is highly likely to be minimal :)
We don't have an allergy-free home but we do buy dairy-free margarine rather than butter, as butter tends to get mixed into jam etc.
New foods - I wouldn't worry too much but would probably try to only introduce one food at a time, just so that if he does have a reaction you know what caused it.
Planes - I think you should do whatever you feel comfortable with. Our issue is dairy rather than nuts so maybe planes are more problematic for you. We have always flown quite a bit as I'm from NZ and DH is from France... the long-haul flights are horrifically stressful and involve huge amounts of organisation, but I still do them.
I don't think you should be forcing yourself out of your comfort zone, but it's good to find out what is an acceptable level of risk really. I do try very hard to make sure that DS1 has as normal a life as possible, while obviously trying to keep him safe. Maybe that's something that changes as they get older - I guess with a baby one is still very much in control of most things, and safety seems absolutely paramount, whereas an older child is starting to have a lot more issues around frustration and feeling different from other kids.
It is a tough road but my DS1 can mostly live like other kids - he goes to birthday parties (with his own box of food and his epipen and other meds), goes on playdates (ditto), has been on two residential school trips (I went on the first one and trusted them for the second, but liaised a lot about food and provided a fair amount myself).
We don't go to restaurants much - mostly we either take food for him, or he has chips or maybe a plate of plain pasta with olive oil.
We usually travel self-catering as it's easier to manage everything.
DS1 went to creche (but it was one where they could only go for half days so no lunch was served), and he takes his own lunch to school.
I agree with freefrommum about the anxiety and learning to relax, and also with londonmum123 that having epipens might make you feel safer. It does sound as if you are taking it all too much on yourself at the moment and maybe trying too hard to make everything safe (when really it's not possible) - don't let it ruin your social life! and I think you may be restricting yourself too much in terms of your own diet (unless you're still breastfeeding).
Keep chatting on here about it, I think it helps to bounce ideas off other people in the same position and find a way of looking at it all that works for you. I think the cbt sessions will also be a big help in figuring this stuff out.
freefrommum I had an interesting birthday party moment this weekend - it's the first year DS2 (age 4, no allergies) has really started going to parties and the funny thing is that he refuses to eat the food! We're not in the uk and here it's mostly just cake and fruit, but he never likes the look of unfamiliar cakes so he always comes home starving. It made me laugh after spending all these years feeling so sorry for DS1 not being able to eat the birthday cakes... though on the odd occasion someone has gone to the effort of doing a dairy-free one, he's never liked it :)