Relationships can be very complicated.
In fact, they usually are. And, being happy in a relationship does not mean it is a healthy relationship. This is difficult because the two people will generally be in denial about several aspects of the relationship. If you are wondering if you are in a truly happy, long lasting relationship, pay attention to the things you have been overlooking. Picture your life 5 years down the road. Will you still be able to overlook those things for that long? Where do you see your relationship after that amount of time? Do you see your significant other supporting you and being there for you, no matter what? Do you see yourself doing the same? You would have to take off the rose-colored glasses to do this, but it is well worth it. You may find that, although you are happy right now, it is because you are overlooking character defects in the other person that will drive you mad later.