[Her concern is not without grounds. If there's anything Reid's learned about himself over the last three weeks is that it's so much easier to change when no one knows you. If one or more of his team members had been here with him from the start, chances were good that he wouldn't have attended the poker night. He may not have gone with Kitty to the movies, or Rebecca for that matter, and he definitely wouldn't have gone out to the club with the both of them. A much more likely outcome would've been that he would've isolated himself to his team, at least to some extent, and never ever allowed himself to latch on to these perfect strangers as much as he had to now.
Had to. Because when you start to rely on something and that something disappears, you need something else to fill the void. Being alone here pushed him to do just that, pushed him to grab on to whatever semblence of a social life he could get because resorting to work or school was no longer an option. Too much dead time, and so you have to adjust. Grow. Fight through the awkwardness of unusual situations, because the alternative was much too painful - too lonely - to bear.
If Garcia would've come sooner, this might not have happened. If she would've arrived within his first week, it would've been too easy to slip back into old patterns, but by now he's far too secure in this makeshift team, this surrogate family to even imagine not having them around. Kitty especially, Rebecca a little less so, some parts of the Defense Force that he's grown to like - it wouldn't matter if the rest of the BAU joined him here, these people would still be in his life. They've claimed their place and perhaps their grip isn't quite as secure as Garcia's or Morgan's or Hotch's, but it's still there.
They're not replacements anymore. She's not a replacement.
That said, he's still pretty glad that they're keeping this to secluded rooftops and behind closed doors. Not because he's ashamed, but rather because he knows all too well how Garcia would deal with this if she found out the full story and he'd much rather avoid the experience all together for a bit longer. At least until they've worked themselves out, until they've adjusted and the mindboggling novelty of it all has mellowed out a little.
So he kisses her a little deeper, pouring in all the attention that was stolen from her that morning. Things may change from now on, his priorities may shift but he's not about to give up on this potential they got going. Not this time.]