Morgan Hawke, an erotic romance author, has tried her hand at cyoa blended with art. Think Hyperstudio, only cool again. The engine is called Ren'py and there's lots of romance to explore, especially manga style, on their site.
Hawke calls her work "visual novels" and the visuals are really lovely indeed. All 3, a fairy tale, a vampire, and a yaoi, are rated X and not for minors. I really wish there were an index or a way to bookmark/save a choice because it gets really tedious replaying to discover other endings. Other than that multi-use quibble, they're well done. Their charm is in their cleverness, not the depth of the story. Check them out!