AFAIK You can't start any new relationships in ME3, only continue existing ones you imported.
- It's very possible to start a romance fresh in ME3, whether it be with a returning character (Liara or the VS) or a newly introduced one (Samantha Traynor or Steve Cortez). Only romances started in ME2 (e.g. Tali or Garrus) have to be continued through imported files. As for the original question, James is not a romance option in any capacity in ME3; the closest you'll get is a one-night hook-up at the party in the Citadel DLC, and that's only for a female Shepard, you can't have an active romance with anyone else and you have to come onto James pretty hard throughout that DLC for it to happen. Plus, both Shepard and James agree that it's a one-time thing and it isn't brought up again for the rest of the game. If you're expecting more, you're SOL. Terminator-HIX