1. They pass the 'bar test
"As simple as this may seem, I call it the 'bar test' to know if you're with the right person. When you're at a bar (or restaurant, wherever) with your new partner, are you looking around to see who else is out there or who might see you two together? Or, are you perfectly content with your partner, and you want everyone there to notice you with him/her? If the latter is true, then he/she passes the test. But if it's the former, it might be time to decide whether being in a relationship with this person is your best option."
2. They don't hold you back
"A person who can authentically be excited about your success and goals in life is someone who won't feel the need to hold you back. Most unhealthy relationships include some form of sabotaging of one partner. Dating someone who is happy with their life means they can be happy for you and alongside of you."
— Shannon Thomas, therapist and author of Healing from Hidden Abuse: A Journey Through the Stages of Recovery from Psychological Abuse
3. They don't want to change you
"When you listen to your heart, you'll feel whether or not the person you're dating is right for you. This is known as 'intuition' — your heart's message to you. Almost everyone can think back and recall a time when they didn't listen to it. When you feel good, feel that your partner is patient and true, treats you the same in public as he/she does at home, then you're on the right path. Keep in mind that your intuition may send out warnings as well. It may come as a gut reaction. For example, if your partner wants to change you in any way. He/she is not accepting you for who you are. If that happens, run. That is a sign of a controlling person and he/she will never treat you properly."
— Tracy Malone, founder of Narcissist Abuse Support.
4. They fit into your life
"A good sign that someone is right for you is if you can imagine that person fitting in to other parts of your life and not just living in a microcosm of the relationship. Ask yourself: Do they get along with the other people in my life? Do I get along with their friends and family? Do we have mutual interests and things that we enjoy doing together that can be a source of sustainability in a relationship? If the answer is yes, then you may be on the right track."
— Holly Daniels, a doctor who specialises anxiety, co-dependency, and relationship addiction at Sober College
5. They listen to you
"One of the signs that your date is likely to make a good mate is that the he or she shows genuine interest in your life and listens attentively when you are speaking. They also remember things that you have told them about yourself.
"Conversely, if the person that you are dating nearly always monopolises the conversation, does not ask you about yourself or your day, and then tunes you out when you start speaking, these are clear signals that your date is not really very interested in you as a person except as an audience for them. If they are not interested now at the beginning of the relationship, they are likely to be even less interested later on."
— Elinor Greenberg, psychologist and author of Borderline, Narcissistic, and Schizoid Adaptations: The Pursuit of Love, Admiration, and Safety
6. They're happy when you're happy
"It certainly helps if you're dating someone that you want to make happy and who wants to make you happy in return. Couples who each truly place the needs and wants of their partners on par with or above their own seem handle a lifetime of compromising, juggling priorities, and collaborating better than couples who individually pursue their own best interests."
— Laura VanderDrift, associate professor of psychology at Syracuse University's College of Arts and Sciences and director of the Close Relationships Lab at Syracuse University
7. They comfort you when you're sad
"One of the major signs that tells you if the person you're dating is right for you is how they treat you when you're sad, crying, having a bad day, or just emotional. Are they compassionate? Are they attentive? Do they stop what they're doing to give you their attention? Are they distracted when you're expressing your feelings and most of all, do they know when to just give you a hug? It may seem simple but this is a very important trait to know what kind of human being the person is. If they criticise you for being sad or tell you that how you feel is silly that you're over-reacting, that may be something to pay attention to. They could show signs of narcissism. Although later, you may think you were over-reacting, it may be just as important to know you were being listened to in the onset."
— Catenya McHenry, journalist and author of Married to a Narcissist
8. They have boundaries
"Something that is important is whether this person has boundaries. Boundaries are important because it means someone isn't a pushover, and they can communicate when they are unhappy. When we are unhappy and we don't say anything, our resentment builds up and boils over. Some women prefer the man to take charge. Some women want the man to be more passive. So you've got to think about your values. In healthy relationships, growth is very important, generally in the same direction, so you need to be able to have arguments, and conflicts and points of disagreements without killing each other. Rather it's an opportunity to say, hey, this is how your brain works, this is how I feel, and can we actually learn from each other in this point in time, and grow in the same general direction, with our own wisdom and our own failures."
— Perpetua Neo, psychologist, expert in toxic relationships and creator of the Detox Your Heart program
9. The balance is in their favour
"One of the first ports of call of an effective narcissist or an effective manipulator is to dissociate you from your own capacity to listen to yourself and your own intuition. Once he's marginalised your intuition, you then marginalise your common sense and your friends and other things. So I think it starts at a very subtle level, to listen to that sense that maybe something is wrong here and just keeping yourself aware of that voice.
"Maybe it sounds a bit cruel, but in the fog of love, we abandon that voice quite quickly, because the other person is quickly perfect. So it can seem cruel to ask yourself, if anything were wrong here, what would I select first about what might be wrong? But when you give yourself permission to ask that question, then the intuition and the hunches can come back. And you may decide that you've considered them, there are ten things you don't like that much, but there are a thousand things you love. Then great, get on with loving them. But ask yourself that question, and give yourself permission to consider those other things. It can salvage your intuition and that part of you for good reason, although that may not be comfortable."
— Jonathan Marshall, psychotherapist and executive coach