Nick is gay, it's not something he tried to be or even wanted to be but it's what he is.
It is also the reason he's not in Dallas any more, the offer to work at the Las Vegas lab was flattering, but he wouldn't have left his family except for the fact that his mother was getting increasingly serious about setting him up with a woman. He could handle it on major holidays, but not all the time.
So being gay was hard for Nick, He sucked at dating, to used to the enforced chivalry he'd learnt from his father and just ended up insulting most of the men the was interested in anyway.
Which was why Greg was such a surprise. He was openly and unashamedly himself and he seemed to like Nick.
It wasn't hard at all, Greg was just there, friendly and affectionate and easy. Nick didn't even really notice Greg was dating him until he kissed him goodnight outside his door after a film.
Nick was shocked for a second before he curled his hands around Greg's shoulder and kissed his back.
Apparently it didn't always have to be hard.