I reckon that Lisbons boyfriend is dodgy. I think that Jane was trying to delay her from going to DC because he knows that hes bad, and then the whole 'I love you' thing was a last resort to get her to stay. Possibly because Jane knows Lisbon felt that way and he prob doesnt cos I found it weird too. Or maybe him and Lisbon both planned it out and were staging something as they have done before. Tricking someone, maybe red john (who could be lisbons boyfriend??)