1. Time, emotions & resources invested
Often I find that looking back at my relationships I was always psychologically justifying to myself why I should continue to be in a relationship where I knew I was settling for less. I would think about the fact that 4 years were invested, how many experiences (both good and bad) we have had together, how I invested to much energy into getting to know him and his family. There are so many factors.
2. Age & effort
When considering a break up or moving onto someone else, the fact that it takes so much effort and I was too lazy to date had a lot to do with it. I considered that my friends who are in relationships in which they settled for, took into account the fact that at 45 years of age it won't be the easiest to start over.
3. Habit and comfort
When you get used to a person, their quirks, your habits of watching your shows together, or doing things a certain way with a person- the habit, routine and comfort all play a role in how you feel. People choose to settle over starting over and getting what they deserve. But it is always a risk.