amat-, amor-, am- +

(Latin: love, loving; fondness for; such as a man for a woman and a woman for a man; an antonym of "hate")

Love at first sight is easy to understand. It's when two people have been looking at each other for years that it becomes a miracle.

—Sam Levenson
amour
1. A love affair; especially, an illicit one.
2. A clandestine (secret) love affair.
amourophile, amourophilist
A collector of valentine cards.
enamor, enamour (British)
1. To inspire someone with love, fondness, or passion.
2. To charm, fascinate, or captivate someone.
enamored
Inspired with love; captivated.
inamorata
1. A woman whom someone loves or with whom somebody has a romantic relationship.
2. A woman with whom someone is in love or has an intimate relationship.
paramour
1. A lover, of either sex; a wooer or a mistress (formerly in a good sense, now only in a bad one).
2. A person who takes the place, without possessing the rights, of a husband or wife; referring to a man or a woman.
3. A lover, especially someone in an adulterous relationship.
polyamorist
Someone who has more than one open romance going on at the same time.

It should be noted that poly means "many", not "more than one".

—From new words and senses from the new 2006 update of
Merriam-Webster's Collegiate® Dictionary, Eleventh Edition.
polyarmory, polyamorous
The state or practice of having (many?) more than one open romantic relationship at a time.
Ubi amor condimentum inerit, cuivis, placiturum credo.
Where love is the seasoning, I imagine the dish will please any one's taste.

This "love" unit is the main contributing source for the words in the ami- or "friend" unit.

Related "love, fondness" units: agape-; philo-; vener-; venus.