Hi, I am Alberto and i have the same car as you with 120.000 miles .
What you explain is normal for me may car alway worked in this way.
At the beginning iwas afraid to see the water rasi 100 C but is normal.
I changed my tehrmostat vale and flus the cooling system, the result is the same.
My next project is tho clean the outside radiator and upgrade the fan cluch, if you do a search about '' FAN CLUCH'' you will find many good information because the maisn problem is that the cluch engage too late and if you lost a little bit of fluid youf cluch spin too much when you are idling.
The auxiliary fan comes on when the cooling raise 105 C or when the A/C pressure switch close............and in the summer this help to cool this engine.
I hope this help you.
Alberto