It's hard to articulate what love is, in our current world in the West, it's hard to pinpoint the meaning of anything at all.
But I think that one of the biggest problems with our understandings of love is that we have blurred being "in love with" and "loving" someone.
At its simplest, being in love with someone is infatuation. That great desire to be affectionate to someone because you find them so attractive, either physically, or because of how kind or thoughtful they are. Essentially, it comes from people being "lovable".
Real love, however, calls for a lot more than that. Love is really tested when the object of your love is "unlovable". If your spouse/partner/friend/child has done something wrong, hurt you or caused you pain, that is precisely when love needs to be played out. And that doesn't fit in with today's view, because relationships are all about getting what you can from them, and if they don't benefit you any more, then time to move on. For the "in love" couple, when the affection wanes, it's time to find a new special someone.
But real love looks beyond the self, and to the benefit of the other. And God so clearly demonstrates what love really is, in his relationship with his people Israel. When God talks of Israel, often he talks of her as a bride, like a wife. But very frequently, scarily frequently, they are referred to as whores. Strong language to say the least. But that is their sin against God, forsaking him, leaving him, the one who truly loves them, for empty worthless things. Leaving their husband and being an adulterous wife. However, God continues to love them as he has made a promise to them to be their God (on which our promises in marriage are made, as men, to be a husband).
Two points to take from this:
Firstly, God doesn't cover up that his people are unlovable. He very much tells it like it is. He doesn't tell them it's all OK, he wants them to change and be a faithful people. For someone who is married, you wouldn't tell them it's all OK to keep having an affair. But secondly, God loves them despite them being "unlovable". Real love is not dependent on the quality of character or attractiveness of the person you are loving, it's dependent on the commitment of the lover.