If they succeeded, it was guaranteed that they would be respected in any major sect, besides Lusserina and Saphielle who might want to go to the elf sects, Luna and Solar could stay at Sword Sect at the request of Zhang Yi.
As Zhang Yi knew his wives' future was assured he could be reassured even if he died after a few dozen more years, but now he just wanted to cultivate to reach the realm of emptiness and be able to find out what happened and maybe avenge his masters before he died.
Since Zhang Yi was always someone who hid his feelings well, his wives couldn't even imagine that Zhang Yi thought about it while cultivating, but even if they knew it, they couldn't do anything to change Zhang Yi's decision.