110 degree flexion is sufficient for your daily activities such as walking, stairs etc.
If you would like to gain more range of motion, continued Physio therapy is required to mobilize the knee as you won't be able to bend it yourself with required amount of force and technique.
Since you stopped PT , if you are not doing any exercises, you may develop some stiffness.
Considering your age, it's better for you to continue PT to regain remaining range of motion.
Though it seems expensive, money you are spending on PT is your investment for future. With each day passing tissues become more stiff, and increased amount of force would be required to get more flexion at knee, if you decided to continue later.
Have a discussion with your therapist about reducing the frequency to alternate days.
Health Tips
Spend more time sitting with the knee bent to maintain range of motion.