Of course there was a time when people used to say that divorce hardly ever happened amongst Jews, though the evidence may have to do with social attitudes.
When being divorced was associated with stigma, it may be that many marriages – Jewish and general – limped along in order to avoid the stigma. The liberalisation of the divorce law has made a considerable difference.
People also say that once upon a time there was hardly any divorce amongst orthodox Jews. The evidence is anecdotal, but it could well be that in homes where Jewish law and observance were central to the couple’s way of living they had a greater sense of partnership.
Statistically, there is certainly divorce amongst the orthodox these days, but there probably are no figures correlating divorce to degree of religious observance.
(Personally I made an attempt at compiling such material in my days with the Sydney Beth Din, but the task was too complicated and I had to abandon it.)
If it seems that the numbers of orthodox couples who divorce have risen, it might be that the fluidity of non-orthodox relationships has by-passed most of the orthodox community and it only looks as though the orthodox have more divorces because they generally take for granted that a relationship needs formalisation and if it, God forbid, breaks down, the closure also needs an act of formalisation.
More important, however, than any of the statistics is the significant phenomenon of orthodox synagogues, rabbis and institutions working harder than ever before to prepare couples for marriage and to help them work through any difficulties that might arise.