Tweaking Your Story Arcs
Sometimes the problem with your romance novel's pacing has more to do with the timing of the events in the story, rather than the tempo of your individual scenes. This usually happens when all of the elements that are needed to make a great romance exist in your plot — though not in the proper order. Tweaking your story arcs can help.
How do I know if my novel's pacing is off?
Sometimes it's hard to be a fair judge of your own writing. Generally, though, if you find your attention wandering while reading a scene aloud, it's a safe bet your readers' attention would wander also. Radical shifts between long, contemplative chapters and short, action-filled chapters are another indication that something may be amiss.
Ideally, your subplots should support your main plot. Not only by adding texture and layers to the main plot, but by supporting it as well, either through added insights into your characters or by introducing new obstacles for them to overcome. The timing of this support, however, is important. If you're having a pacing problem, take a look at the timing of your subplots. Do the highs of your subplots exist during the lows of your main plot?
If not, move the subplot to a new timeframe within your novel.