Settling does not necessarily mean settling for less. Sometimes it means settling for something else.
Let's say that you had spaghetti for lunch. Now you are at dinner with some friends, and you are trying to decide between chicken Parmesan with ziti and chicken fettuccine alfredo. Assuming that both dishes cost the same and have the same calorie counts and nutritional value, which one do you pick? You really want the chicken parm, but you talk yourself into the alfredo simply because you had spaghetti for lunch and you feel like you should have something other than marinara sauce.
This is settling. Not because the chicken parm is objectively, inherently better than the alfredo, but because the parm is what you want.
I have a friend, "Morgan", who is really interested in this guy, "Cal". They dated in college, and after breaking up became best friends. For years, Cal has been in love with Morgan, and in the last few months she has started to fall for him as well. But the last time that they broke up, Morgan's mother attempted to comfort her by saying, "Well, at least now you won't have to worry about having ugly kids." Now Morgan worries about what people might say when they see them together. She worries about the judgement and derision of their friends. She thinks he's attractive, but she worries that others won't. And she worries that her mother will worry about having ugly grandchildren.
Morgan loves Cal, but she is trying to talk herself out of the relationship because she thinks it will be settling. The truth? Choosing anyone but Cal would be settling. Cal is a great guy, and she wants to be with him.
Sometimes we talk ourselves out of our choices because we think that they look like they could be better. We think that we should have a different job because the one we have now doesn't pay very well. Never mind that we are living our dreams. We think that we should be dating a different person because the one we are with is not very glamorous. Never mind that they are the love of our lives. We think that we should choose a different option on the menu because we've had marinara sauce three times this week already. Never mind that marinara is our favorite.
We settle all the time, but not always for less. More often than not, what we are settling for is simply something other than what we really want.