Hi Waxymud
I just came back from Dahab and had a great time there.
Here is my trip report if you want more info.
Things to do in Dahab besides diving and snorkeling include chilling on the beach, going for a camel ride, horseback riding, driving a cart... Most places can arrange day trips to Petra, the white desert or Saint-Catherine, among others. Your wife could also take yoga classes, have a massage in one of the parlors on the boardwalk... Just south of town is a fancy hotel called Bayview Resort & Spa, probably very expensive but maybe the spa is accessible to non-guests for a daily fee.
If you have two weeks, why not spend one visiting sites such as Louxor then go diving and chilling in Dahab for example ? This way everyone is happy.
I wouldn't worry about the bombings. What are the chances of that happening to YOU ? A lot less than exploding your skull on the bathroom tile while getting out of the shower. From the little that I saw, Egypt is a safe and friendly country for visitors... as long as you don't get in a car at night (their driving is insane), drink tap water (the turista is not deadly, but sure bothersome) or step barefoot onto a stone fish.
You don't necessarily have to go through Thomas Cook to "save the hassle".
I bought my flight on the Internet, dealt directly by e.mail with the (rather small) hotel/dive op, they picked me up/dropped me off at the airport at Sharm el Sheikh and they had all the facilities on the premises. I'm sure most medium range places will organize transfers for you.
Wherever you choose to go, just make sure you book your diving with a reputable, long-established and safety-oriented dive center. Red Sea Shadow and Samaka can help you with that depending on your destination.