In modern life, of course, the reasons for divorce go well beyond adultery, and fairly rapid remarriage is common. Evangelicals are part of this modern trend: Many have privately abandoned the Bible's teaching on divorce. American law has pushed them along.
For many years, divorce was a tort--legally possible only if one party to the marriage contract had violated it. Ronald Reagan, as governor of California, signed a no-fault divorce bill in 1970, and within 15 years every state in the union had a similar law. The cultural conversation shifted away from marriage's mutual obligations--codified in law--and toward personal fulfillment.
California's court system couldn't handle all of the divorces, they were being flooded with all of the divorces, so they had to get these divorces done as quickly and as easy as possible. I do not know what Reagan's religious beliefs were, but he certainly made divorce alot easier. Sin is now alot easier, and the state will aid you in sinning easier. No-fault divorce means irreconcilable differences, which is not a biblical grounds for divorce, but the States aren't interested in "biblical grounds". Divorce is a plag on this society, and it is Reagan's bill that assists in progessing that plag.