The CVT will definitely provide you with more comfortable, lower cruising RPMs on the freeway. The engine will be turning around 2500 rpms at 75mph (120kmh). That speed would put you closer to 3800 rpms in a manual!
But I've read enough CVT reviews here that I'm pretty confident that the only time I would like a CVT is on the freeway. At all other times, the manual seems to be the choice for the overall driving experience and fuel mileage. So while I agree with most people telling you the CVT might be a better choice for you, be sure to think about it.
About half of my driving is on the freeway, but it's in relatively short trips of around 15 miles (25km). I'm not comfortable with sustained RPMs over 3,000 (which is completely without reason...it's just a mental thing with me)...so I generally don't drive faster than 60mph. I get passed a lot and I don't get anywhere in a hurry...but I do get great fuel mileage..lol. If I had a long daily freeway commute like yours, the manual might drive me over the edge if I tried to keep it at 60mph. But like MysticMirage said above, I'm happy I went with a manual transmission.
Either way...I would not be concerned about higher RPMs somehow shortening the life of the engine. It was designed to run at higher RPM ranges. It's not a 454 Chevy.
If you have the ability to rent a CVT Mirage, I would consider doing that and using it for a few days of typical driving. See how you like it under all conditions.
Here is a related thread you may want to check out: CVT and RPMs
Before I bought my Mirage, I made a picture of different speedometer images people have posted on this forum. These are manual transmission RPMs at various speeds...
View my fuel log 2015 Mirage ES 1.2 manual: 51.4 mpg (US) ... 21.9 km/L ... 4.6 L/100 km ... 61.8 mpg (Imp)