Quote Quoting veger
Q: Do I understand correctly that my wife's name would HAVE to be on the new deed?
Probably not - although, on the title or not, she would likely have to execute a quitclaim deed at the time you were to sell the property, as property acquired during the marriage appears to be presumed to be community property under Tennessee law. However, if she will be a party to a mortgage on the home, she would ordinarily be named on the deed.

Quote Quoting veger
Q: If anything happens to our marriage, would the house be split 50% with my wife because we acquired it after the marriage?
That's not clear. If you acquire the property with money you have from prior to the marriage, ordinarily you would be able to claim an exception to the general rule of community property. However, where you are contributing only a part of the required assets (albeit a substantial part), the picture becomes more complicated, particularly over time.

Quote Quoting veger
Q: Is there a way to invest my money into the house without making the entire house community property? Can I keep my initial investment separate from the community portion and avoid "commingling"? (bearing in mind that future house payments would have to be from my paycheck which I understand is a community asset.)
There may be a means to accomplish that end. Such as by placing the money into a trust account, and then having the trust lend you and your wife the money to acquire the house, or by placing the money into an LLC and having the LLC lend the money. However such systems have to be properly structured under state law, if they are even possible, and thus you should only attempt this with the assistance of a qualified lawyer within your state. (I believe your simplest solution would have been a prenuptial agreement, but unfortunately it is a bit late for that.)