If you are already fluent in composing and improvising of any sort and your music has been played in concerts and recorded on commercial CDs, then I would say your position is hardly anything to worry about. Most players cannot do these things at all. In creating music I think we have to be completely ourselves; somehow this quality, or the lack of it, always comes out in the music. Struggling with an idiom which is not our natural vehicle, simply for the sake of achievement or to prove a point seems to me a lesser thing.
Of course it depends on your age. If you are young and have plenty of time, then study and assimilate everything under the sun; listen to as diverse an idiomatic range as you can and learn the associated theories and techniques of each. When I was young I had a similar desire to create romantic pieces, fugues, rags and blues, and after years of struggle I managed very reasonable results in all, some better than others. But sooner or later, in my case not until middle-age, you come to the point where you must just be yourself in terms of pure sound, let it out, and say what you must say in any way you can without prior thought of idiom or form.
Follow the others' advice here and study as much romantic music as you can, via both theory and your ear. However, if you reach the end and find it isn't you after all, don't worry too much. Better a fine, original pop ballad written from the heart than a complex but derivative romantic piano solo.