The straightforward answer comes from the experience of Hosea (found in Protestant Bibles in the sequence Ezekiel Daniel Hosea Joel Amos Obadiah toward the end of the Old Testament; in Hebrew Bibles he's one of The Twelve) marries a promiscuous woman, Gomer daughter of Diblaim (no connection to the medical slang). As Gomer is unfaithful to Hosea, so the land of Israel in Hosea's day (and the Church of Jesus Christ in ours) is unfaithful to God.
We find in Hosea's case that Gomer has left him, and like lost son Jesus described, hit bottom. The son, you may recall, squandered his share of the inheritance in wild living and took on a degrading and humiliating job -- a nice Jewish boy feeding swine!
But unlike the lost son of the parable, Gomer wasn't free to return to her husband to ask forgiveness. We read in Hosea 3 that Hosea redeemed her at the then-current price for a slave, which suggests that she had fallen into the hands of slave-traders. Perhaps her debt was too large to pay off? In any case, it was humiliating to say the least -- apparently slaves at market were presented naked, so that bruises and cuts could not be hidden. There she stood, and her husband bought her back.
This is how God loves the Israelites and this is how he loves you and me.
And another thingA bad marriage is still a marriage. Though Gomer deserted him, and she was "loved by another man," Hosea still wanted her. I cannot imagine the heartbreak this must have been for Hosea, and I cannot imagine the heartbreak I am to God.
But I actually wanted to make one more point: nothing worthwhile is easy. Rilke wrote that in his Letters to a Young Poet -- I can't remember the exact reference, as it's been over 30 years.
In particular, any community will have struggles, whether due to external events (e.g., illness, accident, natural disaster, unemployment) or sin or growth (when for example a group grows to twenty and becomes two smaller groups). These things are difficult to say the least, but a community of faith is worthwhile -- no, I'll say community is essential to faith, and I say that as an introvert. But since nothing worthwhile is easy, we shouldn't be surprised when these things hit us. Come to think of it, didn't Peter tell us not to... yes he did.
So I guess my point is, we're to be Hosea to one another, and as the writer to the Hebrews told us, "Let us not forsake our own assembling together" (from Hebrews 10:24-25). And that this won't be easy.
I'm glad Hosea didn't give up on Gomer, and I'm glad God doesn't give up on us, and I'm glad that my brothers and sisters haven't given up on me. So I suppose it's also incumbent upon me not to give up... h'm...