Top three reasons i've seen for Christian divorce (at least in America), abuse, cheating and addiction. Another popular one is one spouse claiming they no longer (or never did) love the other one. So, in my opinion, the actual divorcing is a secondary problem, a result of other, more serious problems, than the divorce itself.
So if people worked harder at helping marriages and focused less on divorce numbers we may see a decline in divorce to begin with.
Also we have to consider that not all Christians initiate a divorce. If neither are saved when they marry, and one gets saved, but not both, the unsaved spouse may choose to divorce to believer.
True some people, including some Christians, are way too casual about divorce, many do seem to spend years trying to repair their marriages to no avail, then end up divorcing. Typically by then they have legitimate reasons for doing so.
As for remarriage, there are various interpretations of this idea. I've not done much digging so i have little insight.