I'm not an expert about relationships, but I know perfectly which behaviors I would never tolerate, or which aspects can create a better relationship. The first advice to achieve a healthy relationship is to support them, to make them laugh, to play with them or even having your own private life apart from your partner. Sometimes we feel anxious to know everything about our partner's life, but you should give them space to have privacy. Another advice, a pretty basic one, is never play around with other people. This will break the trust and it will never again be as it used to be. If you do that, your partner will think that you laughed at them and they might think you are naughty. Even if it wasn't your intention. The last advice is do not look for romance, it will appear when it has to. If you are desperate for love, you will accept everything gladly, and that's not a healthy way to start a relationship.