There must be an equal amount of taking and giving between the two partners. There must also be mutual respect and kindness. Most importantly, there must be boundaries. Recognize that your partner is a separate person with their own needs, values and choices to make. If you think you must have constant closeness, sharing and togetherness, you'll find things becoming suffocating and boring pretty quickly.
Relationships are a primary area for experiencing growth.
Its important that the relationship make you feel safe enough to express your feelings, make mistakes and be yourself. Remember that no other person can make your life perfect. Ultimately, the most important person you must learn to love is yourself.