Romans 8:10

And if Christ is in you, the body is dead because of sin, but the spirit is life because of righteousness.

The original language is very straightforward here. Pretty much, the English words used represent how the original Greek is used throughout the rest of the New Testament. A couple things to note however, are that the word for body (sōma) is used for a living body as well as a dead corpse (see Matthew 27:52,58,59) and that the word for death (nekros) is used both for people who are already dead, but also for people who are not yet dead (Matthew 8:22, 23:27, Luke 15:24). We get so tied up in the current condition of our bodies, which are in a way already dead. In Genesis 2:17 God tells Adam and Eve not to eat from the tree of the knowledge of good and evil because in the DAY they eat of it they will surely die. We are told that they ate the fruit, but they live for years and years. Obviously death means something else. Look at the name of the tree: The Tree of the Knowledge of Good and Evil. The law. There is no evil if there are no rules. The initiation of the law was our choice as humanity. It's just like in 1 Samuel where the Israelites wanted to transition from a Theocracy where God was king to a Monarchy where a man was in leadership. 1 Samuel 8:11-18 is a great outline for the same choice we tend to make of choosing legalism and our own strength over pure love for God. Since the very beginning we have chosen to be subject to the law which only condemns us rather than subjecting ourselves to law of love (the commandment to love God with all our heart, soul, mind, and strength).
...the body is dead because of sin...
It's important to remember that the body is not dead because of Christ. We chose death ourselves a long time ago. He is just giving us a way to be saved from what we already chose.
...but the spirit is life because of righteousness.
Not our own righteousness. Not at all, because any righteousness we would have would be from the flesh, according to the law, which is what makes us dead in the first place. The righteousness is only OF Jesus Christ and accessible to us BY the Holy Spirit.

So What?

Just like the original language in this particular verse is very literal and its meaning is face-value, our choice is a simple, face-value choice. Are we going to keep trying to be good enough in our flesh according to the law that condemns, or are we going to devote ourselves to understanding and applying the new commandment of love? Yes it can be difficult sometimes to know ourselves well enough to see when we're trying to live by the old law, but once we see it, it's a simple choice. We can never be good enough. We just have to grasp that. It's a 2-part process though because we have to let go of our own inadequate righteousness but also grab hold of Christ's perfect righteousness. This isn't just us saying, "Ok yeah, I'll do that. Jesus, be righteous for me." Our receiving of Christ's sacrifice means our receiving of Christ as Lord. As our Lord, we are obligated to obedience, but He makes that simple because His commandment is simply to love Him and love each other. Doing this fulfills every requirement of us.
Keep in mind that loving God is not an abstract idea based on feeling. When you sit down and figure out the time you spend on different things, would that indicate that you love God like you love your family or a significant other that you spend a lot of time with? When you look at finances, what does God get back vs what you spend on yourself for pleasure? When you talk, how often are you talking about your relationship with Christ vs games or movies or possessions? Those are tangible, measurable indicators that could fairly easily show you if you're on track to following the new commandment or not.
Don't just think about it, do something about it. Know where you're at and correct it when you see that you fall short of making Jesus Lord.