Okay, it's Valentine's Day (sort of...) so I'm here to take apart one of the most popular canon Transformers couples...Chromedome and Rewind!
Now, to begin with, I just want to say that I do actually like them as a couple, they were naturally revealed to us (ie they weren't just introduced as a couple, we found out naturally) and they weren't perfect. They had arguments, had differences of opinions, get killed, the normal stuff!
When they have hard times, we feel for them, when they're happy we're also happy. That is a good thing, and something that other forced couples don't give us (Drift and Ratchet, Arcee and Aileron etc)
The main problems with the duo actually come from the real world and seemingly aborted plans for their characters. It is heavily hinted in the early parts of the series that Chromedome was abusive towards Rewind and the latter was only using Chromedome for his Mnemosurgical skills so he could find his true love, Dominus Ambus.
When Rewind first meets Chromedome, he is in a morgue looking for Dominus, or at least someone who can give him a clue to his location, and soon afterwards starts a relationship with Chromedome. He openly is looking for Dominus even after starting his relationship with Chromedome, with the latter seeming to be totally fine with it.
Rewind admits that his main goal in trying to wake up Rewind after his near-death experience was to ask him about his missing lover, which again he was helped with by Chromedome
When the displaced Lost Lighters are giving their final messages to be sent out to the Universe, as they believe that they're about to die, Rewind only talks about Dominus again, showing that even in what he believes will be his final words, he's still only thinking about Dominus
Eventually, when Dominus is found by Chromedome to be the real identity of "The Pet" of the DJD, Rewind chooses Chromdome over Dominus to stay alive. Though this whole situation seems like a forced decision for Rewind to make. Chromedome had no reason to try and de-lobotomize Dominus at that exact moment, they could have kept him isolated until Chromedome had recovered enough to perform his Mnemosurgery later on. It's almost like Chromedome set it up so Rewind had to choose between a healthy husband or an invalid one to live for some reason....
Now, the next point I want to make is speculative, but based on clues from the comic and real world commentary . Quite early on, it was revealed that one characters fate was changed due to the reception of the readers, originally I believed that this character was Tailgate, since I thought he was supposed to die at the end of Remain in the Light, which is why he was absent through the Dark Cybertron event. Later, people thought it was Megatron, due to later discussions regarding his later fate, however this revelation was from before the Dark Cybertron event, aka before Megatron joined the cast, so it must be someone else.
I believe the character who was changed was Chromedome so that they wouldn't have to make the flagship couple of MTMTE be aggressive. As you can see above, Chromedome IS a violent character (I could have added a few other scenes to show this, but one's enough) and IS willing to do horrible things to other people, even people who he has had romantic relationships with in the past (this has been hinted at many times).
My theory is that the dark secret that Prowl knew, that Chromedome made him forget, rather than letting him talk to Rewind was that Chromedome knew what happened to Dominus Ambus, and has known for a while
My guess is that at some point, Rewind may have discovered this secret, and Chromedome used his mnemosurgery to make him forget, explaining the above, forgotten plot point...
Also, as seen above, before Rewind is killed, Chromedome wants to tell him something. We have been led to believe that it is "I love you", however James Roberts is well known for being misleading (look at the identity of Tarn for a perfect example of this) so I believe that he is actually saying "I found him" instead, in an attempt to get Rewind out of the chamber.
Following the Dark Cybertron event, we discover that another Rewind, from the original Lost Light (as our main characters are actually duplicates) is still alive and we get the duo back together. This is where the series most deviates I believe. Originally I think the new Rewind would have discovered what happened from his own crew's experiences and calls out his new Chromedome about his secrets and lies, leading to them having separate quarters, as they do starting in the next storylineAfter the resurrection, the duo do pretty much nothing for the rest of the series, they join the rest of the crew in exploring the Necrobot's planet, where they discover that Dominus is missing, and not confirmed dead. They get involved in the final battle, then travel to the Functionist Universe and do nothing again.
Again, without any concrete evidence, it looks like the duo were relegated to the side-lines of the series, because their main plot line (a fallout due to Chromedome hiding Dominus from Rewind) was cancelled, so they were just reduced to background characters in the latter half of MTMTE and all of Lost Light.
The duo were so starved of any screen-time that they were even the butts of really weird jokes, like the above one were they are discovered "canoodling" INSIDE of Roller's truck mode, as he slept...do I need to explain why this is so wrong?
During the Mederi arc of Lost Light, Chromdome and Rewind are reunited with Dominus Ambus and the other Rewind, and all four of them are shown to be happy and willing to be a quartet. I know that the latter two are just fakes created by the Mederi system, but that is also just weird.
The main reason I bring this scene up however, is that the whole point of the Mederi system is to make you happy, so that you can be euthanized peacefuilly. This clearly proves that Chromedome and Rewind are not actually happy together, even when reunited with their past loves.
Finally, in the main timelines, we see that Rewind ends up being trapped in his alternate mode, and Chromedome has to take care of him, as a full-time carer, all because Rewind decided to download all the information he could about the Functionist Universe, and didn't care about Chromedome's feelings...lovely...
So this was my weird, rambly discussion on Chromedome and Rewind, a couple that I think got edited to hell, and could have been more interesting, escpecially following Dark Cybertron, if they were allowed to continue as seemingly planned.
Like I said earlier though, I do like them as a couple, I have their Timelines and Titans Returns toys, and usually keep them close to each other, I just wanted better for them.
Hey, but at least they aren't the pseudo pedo-couple of Cyclonus and Tailgate...now THAT'S a creepy one!