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Just when you thought your blossoming relationship was going so well, it happens. Your partner grumbles about the check and leaves a bad tip — or stiffs the waitstaff. Debt isn't the only financial habit that can derail a romance. When people aren't on the same page financially, it can spell trouble ahead, according to Jeremy Straub, CEO of Coastal Wealth in Miami, a member of MassMutual. Here are three top red-flag money situations and how to get closer to the truth about your significant other's finances.

Their lips are sealed

First warning bell? Reluctance to talk about money, said Straub, a chartered retirement planning counselor. The reasons vary, Straub said, and they're not always negative. Of course debt is a top reason some people don't want to discuss anything financial. Rich people — either because of an inheritance or because of disciplined saving — can worry that's the reason someone chooses to be with them. Another reason to be tight-lipped about finances: Someone grew up in a family that never talked about it. "They feel it's not something to discuss," Straub said.

Finding out a person's relationship to money is key, but it shouldn't feel like an interrogation. Help someone open up with more general questions. "Share with me how you learned about money when you were a kid" can be a good question, Straub said. The more neutral the inquiry — as in "Did you get an allowance when you were a kid?" or "Do you think kids should be paid for chores?" or "Who taught you about budgeting?" — the better the chances someone will feel comfortable answering.

Are they hiding something?

What someone complains about can signal their finances. "Are they making comments about how much entrees cost?" Straub said. "Or you order an appetizer and dessert, but they don't. "Are they very frugal, or financially in distress?" he added. Listen for complaints about high-interest rates on credit cards or any mention of waiting for a paycheck, Straub said. Another warning sign: Your significant other sports an expensive watch or a Chanel bag but you know their salary doesn't quite allow for those purchases. "You want to figure out if they're all flash," Straub said. Ask for advice or try open-ended questions to gauge their spending habits. "Sooner or later someone will slip or you'll see an inconsistency or a pattern," Straub said. "Nice watch, but bad tipper who always wants to go to Subway. "Ultimately, you are looking for consistency."

Money mishaps or conscious trade-off?

Someone who blatantly lives outside of their means should raise a huge red flag, Straub said, but not all disconnects between purchases and finances are always what they seem. You may need to dig deeper. The designer bag paired with lunch from Subway could be a conscious trade-off, Straub said. People can make well-considered decisions that may not seem sensible on the surface. The woman who sports Chanel but goes frugal on lunch may have decided that high-end accessories are important to her, and she's willing to cost-cut elsewhere to make this possible.

When they tell you more about how they bought their car, you can make some educated guesses about their finances, whether they paid all cash, or leased, which means they have decent credit. Jeremy Straub CEO, Coastal Wealth