Sorry, I don’t do email support (except for paying clients). And I removed your email from sight so you don’t get more spam email.
Splitting WP across two DBs is possible, but I suspect would cause more problems since you have to use a plugin to do it, and I’m PRETTY sure it’s only meant for posts and not the site options.
Anyway. What YOU need to do is go over those files (I’m not doing it, I have a job to keep me busy ?? ) and look at the IPs. If they’re yours, you can remove ’em from the list for now. If they’re NOT yours, just make a judgement call on how many calls from one IP there are. Look up that IP. Does that seem legit? Move on.
The other thing to keep in mind is that since this happens when you POST, and not at other times (that you’ve said) it’s VERY likely that a plugin or setting change is doing this. Be logical. Do you have a sitemap plugin? Turn it off. A ping or RSS plugin? Turn that off too.