Controlling a servo motor with a touch sensor
To solve your problem, you need to take a tiny step into real time programming.  Most Arduino programs deal with one issue or action at a time.  Your simple twist to interrupt and action "i want it to be such that if you remove your finger before the servo reaches 90 degrees that's where the servo stops" requires you to continuously monitor your input (touch switch) while changing your output (next servo position).

You can go about this 2 ways.  You can use interrupts to inform you when the state of the touch switch changes. This is challenging.  Many find it difficult to conceive of what might happen if their program were to be interrupted at any and all possible points in its execution.  A mistake here can lead to unexpected results.

Or you could take turns polling the state of the touch switch then making a small adjustment in the position of the servo.  When the state of the touch switch changes from active to not-active, exit the loop you are using to change the servo position.