P.O.
That's a bad drive no matter how you look at it! I recently moved from Irving to Carrollton and I work in Frisco, so I'm basically swimming upstream to what your husband has to do.
Distance-wise, the tollway/Bush option is best BUT, in that direction, there are many slow-ups. The Bush is good after 35 in the morning, so finding a route to the Bush where you can get on around 35 would be good (for example, take 121 to Old Denton, take Old Denton south to the Bush and then on in to Irving).
As for the evening, I couldn't even hazard a guess... I see it the other way on my way home, but something similar might work. It seems like the tollway is the bigest slow up for going that direction both times of day, so any route that can get around that would work best.
Actually, on the way home, I might try the same thing I suggested for the way in... the slow up on the Bush starts at about Old Denton in the evenings (my daughter stays w/my mom during the day, so I'm coming back through Irving with her in the evenings, but my exit in Carrollton is Old Denton, so I'm able to get off before I get caught by the slow up). Josey is another choice for the north/south portion, but I think it's a little more traffick-y than Old Denton.
Also, I started using Traffic.com recently to get alerts on traffic issues. You can set up multiple routes and set notifications for each route and it will send you emails or even text messages if there is an "incident" on one of your routes so you can take another one. I've found it fairly useful (like most traffic things sometimes the alert doesn't get to you until you're already commited to a path, though).
Hope that helps! Long commutes eat away so much of your time.
P.