My wife was a professional editor before retiring too, and she caught a LOT of things that I'd missed. But then when the publisher's editor(s?) got our manuscript, all kinds of odd things happened. Editing is more than catching errors in spelling and grammar, it extends into arranging text and figures, and anyone who's read our book will be scratching their heads at the way illustrations were put way ahead of when the subjects were brought up in the text, or way after. Things like that - well, we didn't anticipate them, and weren't able to get them changed by the publisher because of pressure to make it "fit with the appearance" of the rest of the books by other authors in that series. There are pitfalls for sure!
One other thing to consider about self-publishing is the whole mess called copyright permissions. If you publish on your own and use a photo or drawing that you've seen a hundred times before in other works, you can still be held legally liable for using it without the copyright owner's permission, assuming it's not 100% surely in the public domain. The common dodge of claiming "fair use" is risky at best, as numerous court cases can attest. It was a relief to have our publisher handle such things for us, although we did have to do the leg work ourselves, getting our sources to sign the publisher's forms.
Good luck, whichever road you take. There's nothing as overwhelming as opening a box and seeing copies of your very own book, with your name on the cover!