Attraction/Interest - Some level of physical and personality attraction that manifests in mutual lasting interest in the other person
(the relationship doesn't get lazy or neglectful)
Flexibility - Both people are willing to accept that things will change a little bit over time and be flexible to grow the relationship together instead of brittle or rigid on many issues.
(you realize that the other person is always changing and growing, but will keep certain core values, and you respect them and their ability to improve and you grow with them)
Integrity/Maturity - Both people build trust whenever possible and admit mistakes when they happen. Both people are willing to admit when they are wrong, or show appreciation for the other person. They see it as a team victory when their partner has a good suggestion or idea, where both people contribute to success without competing to see who had the idea first or whatnot.
(for example if my girlfriend is good at organizing things and I'm not, I back off and let her take the lead on it instead of taking it as a something to get defensive over)
These seem to be very common threads in therapy or relationship books and I'd say they are true from my own experience.
- Response by wp2007
, A Creative, Male, 36-45, Pittsburgh, Artist / Musician / Writer