Valentine's Day and investing in the stock market have more in common than you may think. When it comes to finding love, many people want a relationship that's safe, secure, and lasts a lifetime. Those same qualities hold true when investing, too. While some investors thrive when taking on loads of risk, many people prefer safer investments that will survive all the ups and downs the market experiences over the years. If that sounds like your type, these 500 stocks may be the investment for you. Image source: Getty Images. The investment that will last a lifetime Choosing the right stocks can be difficult, but there's one type of investment that makes it simple: S&P 500 index funds. An index fund is a collection of stocks that mirrors a particular stock market index. An S&P 500 index fund, then, tracks the S&P 500 and contains all the stocks within that index. There are plenty of reasons why S&P 500 index funds are a fantastic investment. For one, the companies within the fund are some of the strongest and most stable organizations in the country. Many of the stocks within the S&P 500 are household names, such as Amazon, Apple, Coca-Cola, and Pfizer. Only the best of the best are included in this index, and by investing in an S&P 500 index fund, you'll be investing in all 500 of these superstar companies. Keep your money safe Another advantage of S&P 500 index funds is that they're one of the safest types of investments available. They're still subject to short-term market volatility, but they generally experience positive returns over time. The S&P 500 has experienced an average rate of return of 10% per year since it was founded. So as long as you stay invested for the long haul, your investments should survive even the worst market crashes. ^SPX data by YCharts S&P 500 index funds also tend to outperform other types of investments. Index funds are passive investments because they simply mirror the index they follow. Actively managed mutual funds, on the other hand, have a portfolio manager hand-picking the stocks that are included in the fund. This makes actively managed funds more expensive, in general. The goal of actively managed mutual funds is to outperform index funds. However, only 24% of actively managed funds were able to outperform index funds over the 10 years ending in June 2020, according to research from Morningstar. Not only are index funds more affordable than actively managed funds, but they tend to see better returns, too. Falling in love with index funds It's hard to go wrong with S&P 500 index funds. They're low cost, low risk, contain some of the most stable stocks in the country, and they're also more likely to survive market volatility. If you're ready to invest in your future, S&P 500 index funds are the investment that can last a lifetime. 10 stocks we like better than WalmartWhen investing geniuses David and Tom Gardner have an investing tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and Walmart wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks Stock Advisor returns as of 2/1/20John Mackey, CEO of Whole Foods Market, an Amazon subsidiary, is a member of The Motley Fool's board of directors. Katie Brockman has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Amazon and Apple and recommends the following options: long January 2022 $1920 calls on Amazon and short January 2022 $1940 calls on Amazon. The Motley Fool has a disclosure policy.Source