I see the dilemma with traveling. In general, I think people should weigh up the positives and negatives: if you know your worries or your physical symptoms will mean the stress of travelling is not worth the pleasure you'll get from it, don't force yourself to go. But as these bad episodes are not common, you may find you put you fears aside once you're there. Just make sure you get good travel insurance (I'm not sure how that works for you in the US, here it can be hard to get cover for an existing condition).
But congratulations on your anniversary.
A marriage that long I am sure you will find a way to celebrate, one way or the other.
Sometimes there are no specific triggers, but a soft, low fibre, low residue diet is probably the safest. Or even a liquid diet, though you must be careful you are getting the calories and nutrients you need if you decide to try that.
When I had ileus and when I had a small bowel blockage, I did get indicators that something was very wrong. With my post-surgery ileus (paralysis of the digestive tract, like a blockage but with no physical obstruction), I was already in hospital. My surgeon had got sick the day after he operated on me, so the doctors I had didn't know me, and I didn't vomit, which is a key sign of ileus, so they missed the diagnosis at first. I knew something was wrong because I was getting worse, not better in the days following surgery and having had many surgeries before, I knew this surgery was too minor to be causing me so much pain. With my small bowel blockage, my stoma stopped working, but I developed stomach pain which was different to the pain I'd experienced with partial stoma blockages before. I did all the things that helped when I'd had stoma blockages - had a hot drink, changed my body position, massaged my stoma - but nothing was helping, and I just knew I needed to get to hospital.
When you have pain, the symptoms which accompany it can indicate whether it's serious: fever is a bad sign; as is a hard, bloated stomach; severe vomiting; the inability to have a bowel movement; or severe, watery diarrhoea. Pain that is constant is more likely to be serious than crampy pain. Also check for dehydration, which causes thirst, lightheadedness and dark urine or a low volume of urine.
So if you have new symptoms that you've not had before, or have symptoms which deteriorate no matter what you do to try and treat them, it could be serious. You should sense when something is very wrong.