How do you know when it's love?

I didn't think that I would find love in my life.  I thought I'd found an approximation of it when I got married the first time, but hindsight has taught me that it was more a relationship of convenience, and less something based in love.  

So what is love?  How do I know I've found it?

Here's what the dictionary says about it:

love

  [luhv]  Show IPA

noun

1.

a profoundly tender, passionate affection for another person.

2.

a feeling of warm personal attachment or deep affection, as for a parent, child, or friend.

3.

sexual passion or desire.

The dictionary has these definitions separate, but I think they all fit together.  When you have a tender, passionate affection for another person, when you have a warm personal attachment, and when you have sexual passion and desire for an individual, you've found love.

How do we tell love from strong infatuation, though?  A person could feel these things, but not really be in love; it might just be a strong, fleeting, desire that feels like attachment.

Here's how I recognized my current relationship for what it is:

• I was happier than I'd ever felt in my life.  Again, could be a sign of infatuation, but I'd never felt happier.
• I could list reasons I felt the way I did, rather than describing a general, nebulous feeling that  couldn't be defined. 
• Nothing was awkward.  Not our conversation, not our first kiss, not the first time we had sex, nothing.
• Her passions interested me, whether or not I shared them completely.
• The "chemistry" was there.  Looking into her eyes triggered deep emotion.
• I went out of my way to make time to talk to her and see her.  I did everything I could to make sure I kept getting together with her, and she did the same with me.  More so, even, because she drives to my place a lot more often (it just makes sense for us right now).
• We were incredibly sexually compatible.
• We were both contributing to the relationship in lots of different ways, and the efforts we made didn't feel like effort at all, even when we were making sacrifices to see each other and do things for each other.  
• She's constantly on my mind.  Still, six months later, my every decision involves thoughts of her.  

I define what we have as love.  If love can't truly be defined, let's call it incredible compatibility, resulting in intense pleasure and prolonged happiness.