Thee things needed in a realtionship
This is the most important thing to make a serious relationship work. But the Beatles weren't right, it's not all you need. But I think with love and determination, you can get to the other two.
You can love somebody to death, but if you aren't getting that across, well, that's a huge problem. You need to be able to communicate both what you need from the other person and to be able to understand what they need from you. I think communication fails more often than love.
Limits to what you can demand. Limits to what can be demanded of you. Limits to how far you'll push, how much you want to know and what you're willing to do. The clearer you are on these (and the clearer you communicate them), the happier you will be. Incompatible boundaries are a huge potential problem, but hopefully love will enable compromise. And if not, well, boundaries can break relationships. But they can also make them work much much better. I'm told this and I beleive it.