So I am in the process of getting the "united we stand" perk from preston, and I finally reached maximum affinity (opted not to flirt with him as I was told it was unnecessary), but I didn't get his perk.

I'm not sure if I missed something, can anyone fill me in?

Same thing happend for me with Hancock. I reached maximum affinity but I didn't get the dialouge box/perk until he had the "final talk" with me so I think that is what you need to wait for. Seems like you can trigger that by initiating dialouge and choose the "talk" option. Or I've just been lucky every time.

What do you mean? I spoke with him and it gave me the additional dialogue items, but nothing happened afterwards. That is of course unless the game lets you flirt with a character prior to having maximum affinity with them.

I have considered the possibility that maybe there is a triggering event such as with danse (or so I've been told).

I think you're supposed to have 4 "special" dialouges with every follower, (not the usual: thoughts, relationship stuff).

Ah, so it's possible that the dialogue with the "flirt" option is not the last one then? I'll keep at it and see what happens.

By The way, I nerd to say This: I flirting a smart, Sassy exchange of words accompanied by meaningful eye to eye and smile...did not expect my follower to jump on me without a warning!("...That was great...") say What!?

There are lots of flirt options before the final conversation. The final dialogue will have a "romance" choice.

Just wait until you get the message that Preston "idolizes" you, that signals max affinity.

Some companions have multiple options to flirt while you gain affinity. when you see Flirt in red as the top action that usually indicates the last dialogue scene with them

Pun intended, I did not see That coming.

Yeah all companions have multiple talks before you get the perk (some also have a quest you need to do first)