…birdflew…

 -The halflife is 42 days for every day spent enamoured, making love a generally slowly decaying compound.  It is important to note that even at halflife, love is still a known Class V carcinogen and the necessary safety equipment must be employed to avoid lovesickness.

-Relative to your carbon footprint: the larger it is, the less you really care.

-Through completely spurious logic, I postulate that the half-life of love can be determined by the sum of the half-lives of the medications which can be used to counteract the symptoms of said “love.”
Note that I am not a doctor, nor do I play one on TV.  And my encyclopedic knowledge of the below topics and figures therein in no way infers that I looked any of the information up.
 
Amioderone:  Used for heart arrhythmia.  Lambda = 25 Days
Albuterol: Commonly used by asthmatics, this helps when you have your breath taken away.  Lambda = 7 Hours
Digoxin:Counteracts your Heart Flutter and fibrillation.  Lambda = 36 Hours.
Fluoxetine:  Active ingredient in Prozac.  Not only smoothes out your depression and panic, but limits the euphoria endemic to new love.  Lambda = 6 Days.
Kytril: Antinauseal/Antiemetic; Used to counteract butterflies in the stomach.  Lambda = 9 Hours.
 
So, assuming one goes through each phase consecutively, a best case scenario is 33 days, four hours.

-There is no definitive half-life in love, just lust. Love has the ability to renew, it is inertia that can cause it to decay, but it is not beyond repair.  I refuse to reduce love to a mathmatic equation. If it were that simple we wouldn’t have been left broken so many times.

-The half-life of love can not be given just one answer. I think it is relative to the the scientist, the subject and the timing of the experiment. The intent of the scientist is important because it sets up the manner with which the experiment will be conducted. The subject is also important because they have to be a willing and enthusiastic participant. If they are neither, the experiment will ultimately…fail. Finally, the timing of the experiment is, perhaps, the most important element in the entire equation. If the timing is not condusive to the hypothesis of the scientist (and subject) then the experiment will not be conclusive.   All 3 elements must be in accord for the experiment to reach a conclusion.

-The half life of love is ideally greater than or equal to the square root of desire, though if that love is pure and does not mix with sulfer or cobalt, then love should last for 60 years, on average. That would make the half-life 30, wouldn’t it? You’re asking the wrong guy.

-It is not a constant, but a variable. The “type” of love can affect this - i.e, infatuation / crushes have a smaller half-life than long standing relationships. If the state of love is strong enough, the half-life point will never be discovered. Most people don’t seem to get that lucky.