Marriage is a major rite of passage and, for many people, the ultimate goal of entering a romantic relationship.

But unlike other personal milestones, such as moving away for university or renting your first apartment, marriage relies on two people weaving their lives, dreams and assets together. For this reason, it's a serious personal, legal and financial undertaking that takes some planning, foresight and a lot of communication to do successfully.

Failure to agree on how life as a married couple will look can easily lead to the downfall of a marriage, with incompatible values and conflicting attitudes toward money cited as two of the most common reasons why marriages break down.

Here is some advice from Barry Nussbaum, a Toronto-based family lawyer who has counselled countless couples, about the details you don't want to skip before getting married.

Don't forget to sign a prenuptial agreement

A prenuptial agreement, or "prenup," is a legally binding contract a couple signs before they marry that sets out how shared assets will be divided if a marriage fails, as well as any expectations around spousal support.

"A prenup effectively addresses the exposure to financial consequences that can result upon a breakup of marriage or, quite frankly, even if parties aren't married and they're in a common-law relationship," Nussbaum told CTVNews.ca in an interview over Zoom. "Don't get married without a prenup, most particularly if you have means and you have financial savings. It's a very smart thing to do prior to marriage."

He said prenups used to be more common in second or third marriages, because at least one party was likely to be older and more established, with more assets to protect.

"Now you see younger people doing it," he said. "They're more educated, they're more sophisticated and people get married later than they used to. So people get married in their mid- to late-30s. They've accumulated wealth, they're more mature, they're educated."

Don't get married without updating your will

Nussbaum said it's good to have a legal will whether you're married or not, and that anyone going into a marriage with a will already prepared should update it to outline what their spouse or children will be entitled to in the event of their death.

Don't overlook values and lifestyle goals

Unlike with a prenuptial agreement, you can't legally bind another person to specific values and lifestyle goals, but you should still make sure you're on the same page about these details before marrying.

Couples should agree on things like where they want to live and how each party chooses to practise — or not practise — religion, but Nussbaum said spending is one of the most important areas a couple should agree on.

According to a February report from the BMO Real Financial Progress Index, more than one third (35 per cent) of partnered Canadians believe their significant other spends too much money and 32 per cent say spending is often a source of conflict in the relationship.

In addition to spending habits, Nussbaum said couples should also agree on work habits.

"How much time do you want to devote to work? Are you both workaholics? Do you want a spouse that's going to be spending most of their time working? I see that as an issue as well," he said.

While couples usually know by the time they get married whether both parties want children, Nussbaum said they can sometimes forget to talk about parenting styles and values.

"It's very important that they're on the same page on those issues as well," he said. "How to raise children, what's important."

Don't get married if you're not ready to commit

Although Nussbaum isn't, and doesn't claim to be, a therapist, he's seen what happens when there's an imbalance in the time and energy spouses are willing to commit to each other and their marriage.

"Don't get married before you're ready to commit the time necessary to the relationship," he said. "Parties have to be thinking about the other person's needs, which are always going to be different than yours, because no two people are the same. If it's always about 'me' and never about the other person, it could be doomed to fail."