Factor of proximity in relationship formation

Factor of proximity in relationship formation       In your post, you mention the factor of proximity in relationship formation. I think this was a really great point because one aspect of forming a romantic relationship is the ability to also have a friendship within the relationship, which encourages a lot of people who were friends first to form romantic relationships such as the examples you gave as coworkers and neighbors. What are your opinions on our tendency to gravitate toward creating romantic relationships with those we are in proximity to or already have a bond with? Do you think it is related to a sense of safety and security or do you think there may be other factors in play