Your post is literally a word-for-word reading of what’s happening in my brain right now. It’s been three weeks trying to figure out what king split bed with adjustable base to get. I usually love me some Reddit for intel but mattress advice here is a losing battle. Heellllpppp More on reddit.com

I love my split king. I sleep better and we keep a few inch gap on our adjustable frames. I ruin mattresses and she doesn't.. I bought a 4.6k intellibed midnight and she is still on last year's purple 4 and my old one is in the trash. For sex it kinda sucks but I'd rather sleep perfectly then worry about that. My wife is a crazy sleeper. And now I sleep better without disturbance. More on reddit.com

If by "split king", you mean two TwinXL beds that you place next to each other without touching, then yes this will work great. But of course you'll have a gap between the beds. If instead you mean two TwinXL mattresses on the same King size bed that either touch or that are enclosed in the same cover/protector, then the benefit will be minimal. Motion still transfers both through the bed frame and through the joint surface between both mattresses. It'll likely improve things a little bit, but I wouldn't hold much hope that it'll make a dramatic difference. More on reddit.com

You know how your partner inevitably creeps onto your half of the bed to cuddle at night? Imagine a small gap in between your spots that they’re now laying on. Not comfortable. You might think this doesn’t seem like a big deal but it’s REALLY annoying. It’s like when you have sheets that want to come off in the corners and you half push it back on so you don’t have to completely reset/change your sheets. Then it just creeps back off when you move a little. That same annoyance can be had with mattresses sliding apart or wearing on the “edges” (now the middle). Some companies are making split kings for the dual adjustable bed bases but I’d imagine it works a little better than two random twin XLs places next to each other. More on reddit.com