See this is why Lucas makes so much more sense as her future boytoy than sadsack...
1 - He's well aware of her actual reincarnation situation and while not closer in actual age (300+>30+>18) is able to treat her as the adult she is rather than a teenage girl he's never stopped crushing on.
2 - They tease the Fuck out of each other and have this really irreverent air to all their conversations that is just not present whenever whatshisface is in the picture.
and 3 - She can discuss the deepest parts of her insecurities and difficulties with him without any need to double talk or avoid topics, because they're both magical beings who want to find the answers rather than someone trying to just 'protect the princess because she's my ethereal love...' *gags*.
It just means that romance will be built on a rock solid relationship rather trying to build a relationship on a shifty romance.