You know you've got a soulmate on your hands when they're not only OK with you changing and growing as a person, but encouraging of it.

"Being willing to push each other as individuals to be better people (not just more successful) is key," Joshua Klapow, PhD, clinical psychologist and host of The Kurre and Klapow Show, tells Bustle. "If one partner believes this and the other doesn’t, the relationship will never grow on equal foundation. Long-term success comes when there is commitment to bettering yourselves for yourselves, and the relationship."

If you two plan on getting married, having kids, or simply spending a great deal of time together as partners, your families will likely come into the mix at some point. And being able to agree on how much (or how little) that happens is key.

"Families are often a point of division in couples, so it's important to agree ahead of time on how [you] will prioritize the relationship with each other and with [your] families when conflicts inevitably arise," therapist Julie Williamson, LPC, NCC, RPT tells Bustle.

What happens if they're rude to your partner? Will you spend holidays together? Are they invited to the wedding? For your relationship to exist in harmony, you'll want to be on the same page.

While it might seem obvious that you and your partner should be on the same page about having (or not having) kids, there's way more to it than that.

You'll also want to agree on how to parent those children, Rosalind Sedacca, CLC, a dating and relationship coach, tells Bustle. "When this isn't agreed upon, the children pay the price along with the parents." And that's not fun for anyone.

You don't have to play the same role when it comes to raising kids. But if you envision kids running wild and free, while your partner wants to be super strict, it might not work out.

It's great if you have a long-term plan, and can imagine where you might be in a year, five years, or ten. But what about even further than that? Do you see yourselves settling down into a quiet life in your golden years, or traveling the world? Or both?

"If one partner just wants to be with family and friends, playing grandparent, and the other partner wants to see the world and travel extensively in new places, the conflict can be troublesome and divisive," Sedacca says. "Talking early on can be helpful in all these issues and reduce the surprise factor. Be open and honest about differences rather than hiding them and pretending they won't crop up."

Couples who do well long-term often come up with a financial plan, and agree to stick to it. As Katie Ziskind, a marriage and family therapist says, "Both partners need to have etiquette and a healthy relationship with money for the relationship to be successful."

Not being on the same page can cause all sorts of problems down the road. So it's a good idea to come to an agreement early on about things like bills, debts, savings, and so on — so that you can avoid potentially relationship-ruining arguments.

Even though it's not always fun to talk about, it's highly likely some form of sexual issue will crop up in your relationship — possibly due to health issues, or other problems. But it doesn't have to tear you apart, if you both agree on how to handle it.

"Health issues may arise and even mental health issues, such as depression, have an impact on libido and sexual intimacy," Ziskind says. "There needs to be other ways of creating intimacy like going for a walk on the beach or giving each other a foot massage. In a long-term relationship, the friendship goes beyond just having sex."

It's totally fine if you're a vegetarian and your partner isn't. Or if they have food allergies and you don't. But if you two are soulmates, you might notice that you're generally supportive of each other when it comes to food, what you like, and what you don't like.

"It might seem strange, but eating habits can turn into a major source of conflict in a relationship," Bennett says. "Topics like .... eating out versus cooking and even dinner times can lead to fights if couples aren’t on the same page."

Of course, you can always smooth over issues like these, if you don't initially agree. But food will likely be one of those magical things you always agree on, especially if your partner is "The One."

Another sign you're meant to live together for years to come? If you can agree on where to set the thermostat — as well as other household-y things — not because you're not allowed to be cold, but because of what these types of arguments reveal.

"The thermostat can be a huge issue for many couples and can lead to a lot of fights," Bennett says. "It sounds silly, but it’s a bigger issue than just comfort. It reveals attitudes about spending versus saving and resourcefulness."

Same goes for cleanliness levels, how you plan to divvy up chores, and so on. If you're going to live a long, harmonious life together, these are the areas where you'll want to agree.

As Bennett says, "You both should at least be on the same page about the role health and fitness will play in your lives (if any)." You shouldn't tell each other what to do, but being supportive of each other's goals can be a major perk of a relationship. Do you want eat more organic foods? Or start walking together after dinner? Having each other's backs, and offering support, can make for a healthy long-term relationship.

If you don't see eye-to-eye in these areas, it may be possible to reach a compromise and have a heathy, long-term relationship. But sometimes, not agreeing in these key areas may mean you aren't a good match for each other — or that you still have a lot of work to do as a couple before you should think about settling down.