IF this were a serious question there are a number of things you can do to prolong your lifespan.
Like other have said, inform the PD (they'll take a report, tell you to beware of strangers and offer sympathy but probably not be much help) and/or the FBI if she lives in another state. IF you have the threat on tape or recording, pay a lawyer $250 to obtain a restraining order against the ex because in some states (like CA for instance) an R.O. becomes your defacto CCW permit (look it up, a number of restrictions apply).
Next, contact Hertz/Avis/Budget/Enterprise and rent a car from them. Ideally something different than what you drive, in a subdued color. It should also have some get up & scoot, just in case. Rent the car for 2 days and then rent a different one (or different agency if you like). Changing cars prevents him ID'ing you by vehicle. Park the rental in a helpful neighbor's driveway overnight. I'll leave you to figure out how to get to it with a minimum of visibility.
Get a cell phone and pepper spray. You can call for help if you discover you ARE being followed. The other can be used defensively without resorting to lethal force if someone keeps approaching you after verbally warning them off.
Change your mode of dress. If you're a suit & tie guy, start wearing dockers and open collar shirts (tell your boss your house was burgled or something). If you're Mr. Blue Jeans, dress up a little. If you always carried your favorite black or brown briefcase, switch to a laptop black nylon case. You get the idea. Distort as many "identifiers" as you can.
If you can afford it, move to a hotel or a "Renaissance Inn". Switch hotels on days you're returning your rental car. If you can't afford it, stay a night or two with a friend, especially those who are alert types.
Speaking of work - NEVER TELL YOUR BOSS of your situation unless you want to be let go ("presenting a danger to other workers"). Instead, claim a need for a 2-week "vacation" due to "serious family matters" and refuse to discuss the details. This will let you concentrate on saving your own hide.
Become predictibly un-predictable. Vary the hours you work, travel, eat, sleep and the places you stay each night or every few nights. Vary your routes to & from anywhere. Don't use the same entrance at work all the time, nor the same driveway. Don't frequent the same restaurants, dry cleaners, etc. If you have to use a dry cleaners, pay someone to pick up your laundry or take it in for you. If you have a maid service at home, stop it. Likewise the pool service, gardners, etc.
If you discover you're being followed, don't panic. Cell phone the PD and drive in a large circular area with a major intersection in mind. Let the cops shake his pockets out. When driving always leave enough room to maneuver your car somewhat, especially at stop lights.
Weapons - Let's not get silly here. Use the handgun you're most capable with as a primary carry gun. I'd personally carry a wheelgun with a smaller BUG - something like a 4" Model 66 and a 2" Model 649 or their airweight cousins. You can carry a third gun in the car that's "more bad" if desired. I'd probably also place a high quality semi-auto rifle in the trunk (An M1A or an AR would be a seriously good purchase at this point, but I'd accept even an M1 Carbine).
I could give dozens more tips. But a couple of serious ones are --
* Always look around you and keep your situational awareness.
* Always think 5 seconds ahead of where you are and where you can go if trouble starts.
* Inspect parking lot areas visually before approaching them and watch for people sitting in other cars. Especially the ones at the far end of the lot.
* Talk to neighbors about strangers in the area (especially those seen when you're not home). Make notes of any strange cars or people you see in a pocket notebook in case the hit man is good.
* Refuse to give up gently - Take the S.O.B. with you if it comes to that.
Last.. if you have kids, get them to your sibling's house, parents home, or with trusted relatives out of state. Get 'em out of school -- and out of state if possible. Be sure the relative is one you trust to raise them if you are killed. And be sure to re-write that damned Last-Will & Testament and get it notarized!
