Firstly there are no Doctors here. There are however members with experiences of different things. I myself have had a triple bypass and 10 stents.
I can understand your fear, and can perhaps calm your nerves a bit. There is no way to predict how long anybody with heart problems will live. Your Husband could very easily live to be 90 or 100. Just because he has had bypass surgery, it doesn't mean a) his lifespan is shorter b) there is no further treatments which can be done if things go wrong. Personally I think his prognosis is very good. You say he's the stressful type, but usually after a bypass you kind of wake up and realise life is too important to worry about. I certainly realised this and used to be highly stressed all the time. I actually find it amusing now when I see people get angry over the most silliest of things, so trivial. Life goes on and things happen if you worry about them or not. Anyway, back to your husbands heart. IF and I mean IF, he develops more blockages or one of the bypass vessels starts to block, there is always Angioplasty, where they balloon and stent the plaque. Blockages tend to form quite slowly so he will have early warning symptoms and be treated accordingly before any damage is done. I think one thing very important in his case (due to stress) is to ensure his blood pressure is nicely in the lower range of normal, even if this means taking medication. You also should remember that research is going on all the time and new techniques are being developed all the time for Angioplasty. I don't think it will be much longer before artificial arteries will be grafted to hearts which cannot block. They have these ready including capillaries.
I often think how lucky I am to be alive today with heart disease rather than 30-40 years ago.Things would have been VERY different then.
And please, be sure that this time he stays on his medication!!
Jesus