Connor stated in his book that he fell in love in late 2014 (if I remember correctly).
He also talked about his break-up and said that the relationship was two years long. The break-up seemed to have happened in early 2016 though, since Connor went with Troye on all of his first shows literally everywhere, but then for the second shows he didn't go and even seemed to "flee" him a bit (so when Troye was coming to LA, Connor was going to visit his brother and also stated so, even though they'd apparently not seen each other for ages, when before they constantly visited each other and fandom knew about their places in the world a lot and they seemed to never be apart for more than a month). also, there were many depressed and highly suggestive tweets of Connor's appearing at that time. so, if all of that was true, they might have started dating in early 2014 and Connor only realized his love a bit later, or they started dating later too and he just rounded up on the two years, or he lied about some dates in order to not make it too obvious, or they still "dated" but where in a heavy crisis in early 2016 but broke up officially a bit later. any of those are possible. (and probably more since i only know those things that they've made somewhat public, you know)
the big troyler flirtation was all throughout 2013 and most definitely early 2014, but it slowed down after that. the 2014 auguest collabs definitely had a different vibe than the highly highly flirty valentine's day collabs (aka boyfriend tag and face painting), and also connor was present while filming. things like italy (where there's footage that seems like troye is reaching for tyler's hand, or they're maybe kissing somewhere, and they were so flirty) and the troyler kiss on stage happened in april/may/june 2014.
(then after that auguest collab, there was later confirmed drama between connor and tyler, and in early 2015 also serious public coldness between tyler and troye. which was when i properly joined, so fun angsty times. good for fanfic writing though.)
tyler stated in binge that he had hookups during a youtube convention in hawaii in early 2014. he also seemed to date around during a lot of this time.
in binge he stays very clear of the shippy business, only talk about other hookups or relationships, and mentions troye a couple times as a good friend.
there's two interviews in june 2015, one where ty praises troye a lot as a friend, and another one where an interviewer (disgustingly so) pushes for a troyler answer and tyler states that they "are not together", but doesn't actually answer the question originally asked whether they were never romantic in any way. (
http://youtu.be/vSud0NRm4gI?t=208)
oh dear god and then there's blue neighbourhood. with some songs that seem to only be possible about tyler, and have lyrics that seem like references to him. (while others are quite obviously about connor, like for him., OBVIOUSLY, or Blue, or Wild probably,...)
imo The Quiet is most definitely about Tyler. but so is maybe Fools. and idk, Troye did say that his lyrics shouldn't be taken too seriously, and that he's never written about Tyler, and his writing process was quite collaborative for some pieces it seems... but then there's the fact that despite all other lyrics being credited to him and Alex (important co-writer), The Quiet is only credited to him. and he seems like a person who highly guards his feelings and isn't afraid to lie to protect them. I think he's quite wary of letting people in so I take his words with a pinch of salt. (he's such a slytherin, honestly. so highly successful, so smart and witty, definitely loyal to family even though they're kinda problematic, and imo guarded against emotional stuff and yeah, not afraid to lie for that)
i am realizing how many things i actually know about the two/three of them and how much has happened, oh wow. there's also an interview where troye states completely unprompted that he "never dated tyler oakley not once, everyone thought we did for a really long time but we never did" (
https://www.youtube.com/watch?v=1iwRO3TxVm4)
my personal interpretation is that tyler and troye did have some sort of thing at some point in late 2013/early 2014, but that neither of them (dared to? wanted to?) make it into something proper. and that then connor came about and stated his feelings for troye much more clearly and they gave it a go and had some good times. and there was drama between connor and tyler, rumoured to be about some coming out stuff but maybe also influenced by this blooming relationship with tyler realizing he did actually wanted to have more with troye...? and then silence between those two as well, with then in mid 2015 troyler sometimes seen hanging out, and late 2015/early 2016 blessing us with, thank god, genuine friendly conler interaction, and for a short time actual tronler hanging out. so in my interpretation, tronnor reconciled with tyler and they hung out as a trio, but then tronnor broke up and tyler kind of sided with connor (at least it was silent between tyler and troye at this point, and being friends with both parties after a seemingly not very friendly breakup would be hard). and now tyler and troye seem friendly again and i hope so so much that tyler and connor still are friends too. if not imma have to yell at tyler for being so stubborn and a bit selfish, no offense, i love you tyler but please be a BIT more considerate and TALKATIVE FFS sometimes
okay wow sorry that was long. and it feels like it's only the tip of the iceberg. man i kinda miss fandom stuff still happening in that area, now i am so unphased (is that called respectful idk)
TL;DR i think tyler and troye were attracted to each other/maybe fooled around in 2013/early 2014, but then the tronnor relationship started and they again broke up in early 2016.