With 3 children will someone be lonely?

My children are currently 4, and 2 (2.5 years apart) and I have been thinking about trying to conceive our third next year. But I grew up as the oldest in a family of 6 and am fearful that the older two will pair off and leave baby number 3 to grow up feeling lonely.

How is or was growing up with 2 siblings? (Or what do you see with your 3 children)