As humans we look for people to understand us, to see where we're coming from, to "get it". Having a nomadic childhood or being mixed, can be particularly isolating, especially as mixed TCKs. So many times we just don't talk about our experiences and how we've learned to cope with the world. Which works (sort of) with friends, but not so much with significant others.
How many times have you said to a friend, or family member, or partner "you just don't understand me." We've all done it. I probably think it on a regular basis. It lets me claim my "otherness" and justify my propensity to keep people at arms' length. Many months ago I rediscovered my Livejournal (remember Livejournal? it's still around). Four months into my relationship with my first boyfriend, I had written "He's just never going to understand me." This was a true statement, and our 21/22 year old selves were very concerned with understanding each other. But ultimately, that wasn't what led to our eventual break-up.
Instead of looking for understanding, maybe we should, instead, look for openness and flexibility. The reality is no one is going to fully "get" another's motivations. Even siblings who grow up in the same house, with the same parents, experience life differently. We all grow and change and look back on things we did in our teens/20s/30s with a "what on earth was I thinking?" attitude.
So surround yourself with people who are willing to listen, really listen, when you talk. Willing to change how they see you based on new information. Willing to let you grow. Because that is how families are made.