When it comes to relating naturally as a romantic couple, this aspect could make it difficult or even impossible. This person may try to control your behavior, both in private and in public. For example, you probably don't feel free to just lean over and give them a kiss, because they'll give you a look to let you know they're not okay with public displays of affection.
When you're together, you feel restricted, sober, rigid and overly self-controlled, as if there are outside forces pushing in on you, making you behave in a certain way. And their romantic expression toward you is definitely cool. The problem is that they want to stay in control at all times, which, of course, is both impossible and no fun, especially when you're fooling around together. Why would they want to maintain such control? The answer probably lies in some past relationships that set up a dynamic for them that they're now living out through you. And the other question is, why do you put up with it? Again, the answer lies in your own past relationships, what you've experienced before and what you're living out again through this one. You automatically set up a dynamic that sets them as the superior and you as the inferior partner. But you're equals, and you should exist as such in your romantic relationship. Where's the romance in trying to control each other and yourselves all the time? It's important to face this problem and deal with it, so it doesn't continue to block the complete development of your relationship.