Darwin accompanied his deeply religious wife to church on Sundays but did not enter, waiting outside for her. Research from Cambridge suggests his delay in publishing " Origin.."was due to ill health, in part, combined with a heavy workload. It is considered a myth that he delayed due to religious sensibilities or that he feared censure. He had gathered such vast amounts of evidence supporting evolution via natural selection it would be unthinkable that he could any longer believe the biblical creation narrative and thus Christianity at the very least.
When Astronomer Royal Martin Rees was asked why he still attended church his reply was " loyalty to the tribe".Don't know why I wrote that but it seemed appropriate, somehow.