The Lovers is one of those cards that only means what you want it to mean part of the time. Yes, it can indicate romantic love. Yes, it can indicate a marriage (see Interactions below), but the image on the card is a depiction of Adam and Eve from the book of Genesis. This is primarily a card of choices.
If you get this card in a spread, look at the cards on either side of it. Those cards want to be in balance with each other. They want to be in relationship with each other. Your message is to choose between what those two cards represent.
The Lovers card reminds you of your responsibility to make an important choice. You must choose to eat the apple, an act that could get you thrown out of Paradise. You must choose if you will to merge with someone (or something) else, an act that will make you aware of your own boundaries. Each choice causes a series of reactions down the line. Each choice makes you aware of something that was hidden to you before. Look around you. Make the best choices you can. Your life is about to change in reaction to your decisions.
In a spread, the Lovers either speaks to romance and marriage, or indecision. In a spread, look at the cards on either side of the Lovers. The Lovers will often show a connection between those two cards. Those cards will be attracted to, or balance each other.
Magician: If the Lovers comes before the Magician (Cobbler or Magus in other decks), it signifies indecision in starting something new.
Hierophant: If the Lovers shows up in a spread with the Hierophant, it can indicate a marriage.
Chariot: If the Lovers comes before the Chariot, it indicates a betrayal. If the Lovers comes after the Chariot, a sudden departure will end a romance.
Death: If the Lovers comes before Death, it indicates the end of a romance.
Temperance: When Temperance is next to the Lovers, it indicates indecision.
Four of Wands (Clubs, Rods, Staves): If the Lovers shows up in a spread with the Four of Wands (Clubs, Rods, or Staves in other decks), it can indicate romantic love or marriage.
Two of Cups (Hearts): If the Lovers shows up in a spread with the Two of Cups (Hearts in other decks), it can indicate romantic love or marriage.
Ten of Cups (Hearts): If the Lovers shows up in a spread with the Ten of Cups (Hearts in other decks), it can indicate romantic love or marriage.
The Suit of Swords (Spades): If the Lovers shows up in a spread with any of the Swords (Spades in other decks), it indicates the end of a relationship.
The Major Arcana
The twenty-two cards of the Major Arcana tend to hold the big lessons. These cards carry powerful messages. If you are reading a spread of cards, watch for the Major Arcana. If your spread contains more than 30% Major Arcana, you are in the midst of something big, or beyond your control. If most of the cards in the spread are from the Major Arcana, you might be trying to exert too much control. You might have trouble expressing your feelings, or you might be near your breaking point. A spread without any Major Arcana cards could indicate you are hiding from the truth of the issue, or are in some deep distress. If this is the case, it is important to find someone you can trust to guide you through this period of time. In a spread, focus most of your attention on the Major Arcana. The other cards will be useful for clarifying the situation.
The Number — 6
Six is a number of knowledge, perfection, and exchange.