100km EVERY DAY ?, 5 days per week ?. That's 300 miles per week without the weekend warrior hammer fests.

I wouldn't do it.

I used to manage about 150 miles/240 km per week commuting, 2 RT's at 54 plus a park and ride of 36 RT. I was 20 years younger, racing and could do 200-300 mile weeks on the bike.

It takes a huge toll on you, unless you are used to putting in 6,000 - 7,000 mile years. I was tired after work and found myself not paying attention to the conditions, which is especially a problem if you do the same route every ride. Then you are susceptible to near misses and other potential accidents. As well I learned to never race the route to save time as that made me more vulnerable to accidents. I was also single for the most part so had the time to deal with all other life requirements.

Is it doable - Yes.