A woman I'll call Lucy thought her family had reached the Promised Land. After ten exhausting years of supporting her husband and his startup, including raising two children mostly on her own, the end had arrived. The company had been sold, and they were suddenly rich beyond their wildest dreams.

But Lucy's dream of peaceful domestic bliss never came to fruition. Shortly afterwards, her husband came and asked her for permission to sleep with other women.

Lucy--a real woman in Silicon Valley, who told me her story on condition of anonymity--is certain that this deep betrayal is related to her spouse's successful exit. "There's a fantasy that gets portrayed," she told me. "One day he'll be done with his company, we'll ride into the sunset, and everything will be hunky-dory. But that's just not real."

Instead, Lucy's husband was showered with accolades and acclaim. Important people told him how amazing he was and how he could do anything he wanted.

This sudden, overwhelming surge of ego-feeding affirmation went to his head. The man who had been Lucy's best friend and closest partner for seventeen years became someone she no longer recognized.

Horrified at his request to sleep around, she said no. The many fissures that had formed in their relationship over the past decade came boiling to the surface. They fought constantly. At one point, Lucy told him, "I don't think I can respect you anymore. You're a jackass now."

Unfortunately Lucy's experience is not unique. A deeply personal price--to our character and our relationships--can come with that mythical billion-dollar valuation. There's even a term for it: Sudden Wealth Syndrome (SWS).

Typical symptoms include stress, isolation, guilt, and fear of losing money. At the root of SWS is a deep, expansive identity crisis: the rapid shift from being a typical, hardworking Joe or Jane to a person of extraordinary privilege and status.

Though entrepreneurs might toil harder for their wealth than, say, lottery winners, the end result can look the same. Successful entrepreneurs are still prone to squandering their money, divorce, loneliness, depression, even suicide. They can also become narcissist jerks who end up deeply hurting or alienating those around them.

For those who think a windfall might be coming, getting sound financial advice is certainly a good start. But I believe the identity issue is far more critical.

Recent studies have shown that the more wealth someone has, the less generous and empathetic he or she will be. Children who grow up in extremely privileged households tend to be less resilient and more disconnected from others.

If you are hoping for a ludicrous exit without damaging your family, your integrity, or your well-being, the odds are actually stacked against you. So it's best to prepare in advance for the possibility. Here are five steps you can take to safeguard yourself and your family:

1. Be certain of who you are--the good, the bad, and the ugly.

Even more importantly, remember that is who you will still be after you become wealthy and successful. The number of zeros in your bank account and the admiration you receive from others don't determine your identity and your character; you and your actions do.

2. Talk frankly with your spouse about the risks and possibilities of hitting it big.

How would you use the money? How will you talk about (or not talk about) your wealth with friends and family? What pitfalls--financial and emotional--could you see yourself falling into? Come up with a game plan for addressing these concerns.

3. Don't plan to make any major changes to your lifestyle any time soon.

Warren Buffett still lives in the same house he had before he became a multi-billionaire; his children didn't know how rich their family was until they were adults.

Continuity and stability are healthy for you and your family. Lifestyle changes are best incorporated gradually and thoughtfully rather than spontaneously.

4. Invest in trusted friendships and financial advisers now.

Large sums of money bring out all sorts of strange characters, so it's wise to build strong, authentic, reliable relationships before people get distracted by all those dollar signs.

5. Accept that there is no such thing as a Promised Land.

Business success, just like business failure, brings challenges. You and your spouse will still fight; your children will still throw tantrums; finances will still cause stress.

Instead of looking to material wealth to improve your life, focus on making choices that propel you toward prioritizing what matters most to you, whether that be loved ones, a sense of purpose, or creating something meaningful.