The fact that you're thinking and asking about this is a sign of growth. It seems to me the best thing you can do is allow yourself to be drawn further down that path.
What you wrote strikes a chord with me. I grew up frequently being told how smart I was. Since this was most of the positive feedback I received, my concept of myself was heavily biased that way. But life intervened and I was forced to change. Among the conclusions I drew is that knowledge is no basis for identity.
For me the shift came from seeing that the cognitive intellect is not as important as it thinks it is. (I love Emo Phillips' line, "I used to think that the brain was the most wonderful organ in my body. Then I realized who was telling me this.") It wants to live in a world where it's at the center, figuring things out and making decisions, but this is largely a fiction. In recent years there have been a host of experimental results demonstrating this, but wise people have said it forever and I think many people feel it instinctively. To those of us who have grown up identifying most with the cognitive mind, this is a challenge.
The reason relationships suffer if you place too high an emphasis on being smart is that you're paying attention to only one channel and are closed to other ones (emotion, intuition, etc.) that have a greater role to play. You can easily be "right" in everything you say and do, yet end up in a colossally wrong and pathetic position, unable to understand why people react to you the way they do. Meanwhile those other people are wondering how you could be so oblivious.
The issue here is not how smart one is, but rather the need to be smart, which is ultimately the need to be seen as being smart. That is not a cognitive need, but an ego defense. It gives you something to be; it tells you who you are; it assigns you (the smart one) a high status. But it's grounded in fear: if I'm not smart, what am I? who am I? what value do I have? (The fear being, I'm nothing, I'm worthless.) This is a weak position to live from. Maybe you can get by, but reality has a way of contradicting it, such as when other people don't conform to the script.
The best way out of this that I've found is simply to learn to be ok with not knowing. When you switch your default position from "I know" to "I don't know", a lot of things follow. It's a tradeoff: you don't get to feel particularly smart or special any more, but in exchange, a lot of the hitherto frustrating and impenetrable aspects of life start to go better. Basically, you stop optimizing for a local maximum and get pulled into the main current.
Edit: it's good for creativity too, because you stop fighting for your ideas and become open to more and better possibilities.