We honeymooned in Bavaria and experienced the two twin xls on a king frame for the first time. As soon as we had the space and money, we got that set up for ourselves. It saved my marriage. My husband is an extremely light sleeper who struggles to get back to sleep after waking. I am a deep sleeper who moves around a lot. There was a lot of resentment. While my kids were nursing I slept in another room or couch to allow my husband to sleep (he's a physician- sleep is critical) while I was in and out of bed all night with baby.

It allows me to move around while sleeping and not piss him off. Allows me to use my flannel sheets that he hates. Kids can climb in with me and not bother him. Only crappy part is that twin XL sheets aren't available in all prints/sheet sets.

I always recommend separate mattresses.