Ok ok, counterpoint; sentoprachnia + megs. Before Blackarachnia has a chance to leave the Decepticons to win back her exes, she's ranting and raving about Megatron stealing her boys when he turns right the fuck around and starts flirting with her too. Her brain just kinda, shuts off trying to process it cause there's no way right? He was just fucking with her by trying to go after her Primes and now is pouring salt in the wound by flirting with her, right?!?
I mean, it's a win-win situation on all sides. Optimus gets his friends/lovers he's been trying to reconcile with for years back on top of wining the affection of his secret academy guilty-pleasure crush. Score.
Sentinel won't ever fucking admit it, but he's quite happy with this turn of events. Three ridiculously attractive, talented, and powerful lovers?! What's the downside here? Ignoring the fact that one is a techno-organic mutant that used to be his girlfriend whom he thought was dead, the other his boyfriend in which he betrayed and belittled so badly that it impacted his self-esteem (and also thought was dead for 50 years), and the third being the LEADER OF THE FUCKING DECEPTICONS, but let's not focus on that shall we :)
Blackarachnia of course gets her boy toys back and presumably calms the fuck down enough to forgive and start taking responsibility for her own short comings (the same can't be said for Sentinel, without coercion) but gets to bag her boss on top of that?? She 100% knew about Optimus' crush and goddamn she can't blame him.
And Megatron gets three talented young mechs all to himself. The brilliant techno-organic spider beastformer scientist he picked up on a whim from a desolate condemned planet, then her two boy toys that are, 1) the Magnus' right hand mech and a powerful Prime in his own right (ha. Suck it, Maggy) and 2) the mech he's had his optics on since he got shoved out of the goddamn airlock by him and then systematically thwarted his plans and took him down damn near single-handedly with nothing but his rag-tag crew of TECHNICIANS in Under A Year. Oh yeah, he's bagging and tagging these three in seconds, no Magnus you can't have them back, not even Sentinel, they're Megatron's now.
Believe me I absolutely considered this myself, and it would be fascinating and such a fuck you to Ultra Magnus gsgsgdgdgfhf