Here's how many years a relationship expert says to wait before tying the knot

In some ways marriage has taken on a terrifying role in today's society because of what can come after: divorce. It's not an unreasonable fear considering an estimated 40 to 50% of married couples in the US have divorced.

But, anthropologist and human behavior expert at Indiana University who's spent decades studying different aspect of love, Helen Fisher says that if you wait about two years before getting married, it could boost your chances of leading a happy, life-long marriage.

"There was a recent study in which they asked a lot of [dating] people who were living together ... why have they not yet married and 67% were terrified of divorce," Fisher said on Big Think.

"Terrified of not only the legal and the financial and the economic but the personal and social fall out of divorce."

Interestingly, this fear of divorce is actually giving way to healthier marriages, overall, because people are taking more time getting to know each other before tying the knot, Fisher said.

And time is the only one way to reactivate a part of the brain - responsible for logical decision making and planning - that shuts down when you first fall in love with someone new, which can explain the irrational behavior of two people who are madly in love:

"One of the problems with early stage intense feelings of romantic love is that it's part of the oldest part of the brain that become activated - brain regions linked with drive, with craving, with obsession, with motivation," Fisher, who has studied the brain on love, said. "In fact some cognitive regions up in the prefrontal cortex [shown below] that have evolved more recently begin to shut down - brain regions linked with decision making [and] planning ahead."

This intense feeling of love can cloud your ability to think logically or rationally about the person you're with. Therefore, by allowing time for the brain to adjust to the new situation and feelings you're experiencing, you can recognize whether who you're dating is actually right for you.

"I think ... this slow love process of getting to know somebody very carefully over a long period of time is going to help the brain readjust some of these brain regions for decision making," Fisher said. "You're going to get to know how this person handles your parents at Christmas ... how they handle your friends, how they handle their money, how they handle an argument ... etc."

Ultimately, you want to get a good sense of your partner's behavior during these real life situations, which is why Fisher suggests to wait at least two years. That way, you've been around the annual treadmill of life twice with your partner, and, therefore, should have a good sense of how they handle themselves under different circumstances.

"I think people should marry when they feel like marrying but from what I know about the brain if it were me I'd wait at least two years."