A few things first- while you might read my o/o's or other writings and see some fairly extreme things there, here I am looking for some gentler, dare I even say vanilla romance and sex. Although there could still be some room for some extreme violence in the first story idea, I'm not really looking to mix the violence and sex.
One more thing- please note the liege badge... if you are one of those who needs to know that your writing partner has female parts, then I am not the droid you are looking for. (I hate to even have to add this, but recent events make it necessary).
Now on to the ideas!
Our characters meet, and feel an instant connection to each other that we can't explain. We decide to go on a few dates and see if we can figure out why we feel so close to each other, and as we get closer, we start to experience dreams and even waking flashbacks to a previous life. In that other life, we had fallen madly in love with each other, but just before we were about to consummate our passions, we were taken away, languished in bonds and then eventually executed together. Eventually we fully recall this past, then realize we are back together, with the freedom to explore the passion that we were so cruelly denied before.
My character will be female, both her current life and in her past one. Your character can be whichever you wish, and even different genders between the two time periods if you wish. The time period for the flashbacks is totally up for discussion- anything from prehistoric, ancient times, medieval, recent history, whatever we decide. We could even have them meet up through several incarnations, each time pulled away from each other at the last moment, if that sounds like it might be fun to write.
The Ugly Duckling
My character is a typical geek/loner type, with a very diminished self image, partly because she has no social skills, and partly because she has an abusive father who is constantly telling her how ugly she is. In truth she is quite pretty, in a natural sense, even though she never does anything to enhance her attractiveness because she feels it would just be a waste of effort.
That's where your character comes in, he or she is the most popular student in their senior class, with all kinds of self confidence and pretty much every advantage in life. Your characters doesn't even know that mine exists, until one day she does him or her a pretty serious yet unsolicited favor and your character comes to realize how badly she could use a friend, or even someone closer than a friend.