I think this would largely depend on your own mindset.For example, somebody with a victim mindset who is unwilling to work on themselves and only complain, I would reckon itu2019s more likely that over time they could become jealous of their partner and even resentful when they see the traits they wish they saw in themselves.It could also lead to choosing a partner based on superficial traits that are desired rather than on a solid and deeply genuine connection.Or maybe it could even lead to an overwhelming infatuation with their partner masquerading as love.On the other hand, if a person has a growth mindset where they genuinely want to try and solve their problems rather than complain about them, then partners with differing traits could really help to round each other out. Though, Iu2019ve known this to happen with couples who are extremely similar as well.Iu2019ve seen couples where one is borderline neurotic and the other is horizontal theyu2019re so laid back. And as Iu2019ve known them, Iu2019ve watched them both slowly mellow each other out until theyu2019re both (mostly) balanced in their tempers. She taught him to become more responsible and express himself more often, he taught her to lay back and feel less guilt over taking days off from work.But then, Iu2019ve seen couples where it is like theyu2019re looking in personality mirrors. And they also taught each other to mellow out. She would see him fly off the handle and realise that thatu2019s what she looked like when she got angry. He would see her become immediately defensive in arguments and realised he could learn to be more apologetic.Rather than seeking somebody with specific traits, I think the most important thing is that the person makes you feel comfortable, safe, at ease in your own skin, you have chemistry, you can rely on each other when things get tough, thereu2019s no scoreboard, youu2019re both willing to put in the hard work a relationship deserves, and you enjoy spending time together (mostly, because of course there will be days where you want to - figuratively - ring each otheru2019s necks).That said, I do believe that having a few non-negotiables is important, but I consider them more serious matters. For instance, nobody will look the same forever (except maybe a celeb with their face stapled to the back of their head), so I donu2019t consider beauty a non-negotiable.Sure, you want to be attracted to them, but a perfect 10 is only that to a handful of people and only for a good 5u201310 years before that handful gets bored and looks for a younger and fresher model. In my opinion, but I know that others may not agree, when you fall truly in love, theyu2019re always a perfect 10 to you, even on the days where you want to slam your own face into a wall with their (and your) antics.Kids, however. Thatu2019s a non-negotiable. If you donu2019t agree from the beginning, it can turn out a very ugly affair as you both expect each other to change your minds but neither of you do. Itu2019s heartbreaking when this happens to couples who had never discussed it before or assumed the other would change.Money is probably a non-negotiable for many people too. I donu2019t mean as in u201cthey must be richu201d. I mean it in a sense that your values align (e.g. you both see the importance of saving and investing, but you also both like to enjoy some of your money going away in the summer). It can be an extremely friction-inducing topic between couples who donu2019t openly discuss their attitudes toward it.To sum up, because I went on a slight tangent there, I believe that seeking a partner that fills the gaps in yourself is very dependent on the people involved and the stages of life theyu2019re in.It could help to round a couple out, but it could also create a sense of insecurity in one or both partners as they cover up their perceived flaws with another person. It could help you to see what you lack or could work on, but it could also become tainted with jealousy and spite. It could turn out to be the best partnership of your life, but it could turn out the worst.In my opinion, there are more important things to look for in a partner than just somebody who fills your blanks. Be comfortable with your blanks, but still open to learning how to work on them.