Okay so I don't normally listen to rap but there is this song that I love to beginning of and it starts kind of electronic I think and has a girl singing about getting lost in a guy's love or something. I forget but it is about 4 lines that goes:

1. I don't know/ remember
2. Same ^
3. I want to get lost in your love (or something along the lines of that)
4. Same as 1 and 2.

After that a guy starts rapping about something I don't remember and throughout the song, the girl comes in periodically and sings the same thing.

"Lost in your Love" by R. Kelly:
http://www.youtube.com/watch?v=J1ntQjv6Joc

Not exactly described as you did... but definitely has the line you mentioned...

Thank you! I figured out the song, and believe it or not those weren't even the lyrics, but they were the only things I would think of. Turns out the song was actually Just Can't Get Enough by Black Eyed Peas. I am so embarrassed but happy I found the song!