If an Aries is on the fence about their relationship, boredom may very well be the thing that pushes them over the edge.

"Adventurous Aries people thrive on excitement and can’t stand boredom," Alexander says. "If your relationship starts falling into a routine, [they] may pick a fight just to stir things up." Or even decide the relationship's not worth it.

One way to prevent boredom from ruining an otherwise-healthy relationship, is to keep things fun and exciting as a couple. This might mean going on more dates, taking an extended vacation, or trying new things that push you outside your comfort zones.

As a sensual sign, it doesn't take much for Taurus to feel distant in a relationship, if they aren't being fulfilled in the love department.

"[Sex and intimacy] make them feel loved and valued, so a lack of interest in physical intimacy [can] leave them unfulfilled on many levels," Alexander says.

Of course, if a Taurus isn't feeling fulfilled in their relationship, they need to speak up and let their partner know. Once they do, they can figure out ways to keep the spark alive.

Since Gemini is all about communication, they can fall out of love with a partner who doesn't do so effectively.

"Gemini is the sign of communication, and it’s essential for people born under this sign to be able to talk — and talk and talk — to their partners," Alexander says. "Sharing ideas stimulates them, and they’ll quickly write off partners who can’t hold up their side of the conversation." So stay open with your Gemini partner, and they will appreciate it greatly.

As one of the most family-oriented signs, Cancer places a ton of value on their home life. So one thing they have little tolerance for is any negativity towards their family.

"Their loved ones and heritage give them a sense of security and belonging, and they’re intensely loyal," Alexander says. "Criticize a Cancer’s family and [they] will take it personally — and might show you the door."

Leo craves attention, but only if it's the good kind. "These proud people need to shine like the sun, which rules this zodiac sign," Alexander says. If their partner ever makes them look bad or embarrasses them in public, the relationship isn't likely to last long, which is something to keep in mind when dating a Leo.

Virgo is the sign of orderliness, so they can be incredibly irritated by a partner who is sloppy or messy, Alexander says. "They can’t bear disarray, in the home or workplace, and believe there’s 'a place for everything and everything in its place.' The quickest way to annoy your Virgo partner is to leave clothing scattered about, piles of paperwork on the floor, or dishes in the sink." It may not seem like a big deal, but this will really irk a Virgo.

One way to navigate any potential troubles is by being honest with each other about these quirks, and what you expect from each other in terms of chores, cleanliness levels, and so on. By coming to an agreement, a little mess doesn't have to end a relationship.

If anything's going to push a Libra away, it'll be a partner who doesn't keep up their end of the bargain when it comes to cleanliness.

"Libra is the sign of beauty, and for these people appearances count big time," Alexander says. They're very tuned into their surroundings, and may be entirely turned off by a partner who doesn't care. In which case, this is something you should talk about with a Libra partner if it becomes a problem.

A Scorpio may end a relationship on the spot if they sense their partner is doing something behind their back. "Infamous for their jealousy and possessiveness, Scorpios demand exclusivity in a relationship," Alexander says. "They won’t tolerate infidelity and have a sixth sense for cheating. Even casual flirting could be cause for a Scorpio to end a relationship."

But that doesn't mean all their relationships have to go up in flames. By setting up healthy boundaries from the get-go, Scorpio will feel more secure with their partner. They should also work on their trust issues — both alone and with their partner — so they don't have to live a life of suspicion.

While all relationships need boundaries, Sagittarius tends to overreact if and when they feel boxed in. "To be happy they need their freedom (or at least the illusion of it)," Alexander says. "Sagittarius is the sign of travel and these folks like to be on the go, always exploring and expanding their horizons."

That's a great quality to have, and one that may not initially mix well with a stable relationship. But that doesn't mean all hope is lost. "Instead of attempting to limit their questing nature, join them on their excursions," Alexander says. The best partners for Sagittarius are ones who are just as adventurous.

Capricorn is no-nonsense when it comes to their careers, their futures, and their finances. So they really can't stand it when a partner lets them down or shows signs of not being responsible.

"Pragmatic Capricorns have a knack for managing money and take financial matters seriously," Alexander says. "Maxing out your credit cards — especially on nonessentials — will surely alienate a Capricorn partner, who sees being in debt as irresponsible and unacceptable."

Money is a tough subject to talk about for all couples, but may be even more difficult (and important) when a Capricorn is part of the mix. It may help to talk about money early on, to make plans together, and to create a budget — so no one feels put out.

One thing that's extremely important to Aquarius is that things remain fair and balanced within their lives. So the moment their relationship feels unequal, they may want to back out.

As Alexander says, "They won’t tolerate a relationship with a mate who holds most of the power. These independent people seek genuine partnerships, where decisions and responsibilities are shared equitably, and will rebel if one person insists on calling the shots."

If Pisces feels like their partner is no longer sweeping them off their feet, they may start to second guess their relationship — or even get a bit resentful.

"For dreamy, sensitive Pisces, romance is essential to a happy relationship," Alexander says. "They adore flowers, candlelight dinners, love poems, and all the other idyllic images of romance."

Of course, it's not fair for Pisces to expect these things every single day. But they may want to look for a partner who's equally into romance, so they're less likely to feel letdown.

By paying attention to what matters most in a relationship, each sign can help their partners feel fulfilled, while also making sure they have their needs met, too.