(CNN) -- Gowns have been fitted, caterers have been contracted and venues rented as June marks the busiest period of wedding season.

dating for 7 years before marriage-83

Now people get married because they want to have kids.

Now there is a sense that marriage is a sense of adulthood.

People want to be fully formed before they get married.

For example, the day-to-day staple activities are done together.

You buy furniture together but you say, "What happens when if we broke up? " There is no definite sense this will culminate in marriage.

CNN: Why are people having these lengthy monogamous relationships that don't result in marriage?

Seligson: It used to be you got married for economic reasons. It was too risky to have sex outside of marriage because there was limited access to birth control.

Seligson: My baseline is one year in a monogamous relationship.

Do you see this as someone you are making big sacrifices and life decisions around?