骑虎难下 (qí hǔ nán xià): if you ride a tiger, it's hard to get off ; fig. impossible to stop halfway

骑qí虎hǔ难nán下xià

if you ride a tiger, it's hard to get off ; fig. impossible to stop halfway

Once you are on the tiger, getting off is the dangerous part. For the commitment that has become harder to abandon than to finish.