I just heard that one reason given that a Kohen may not marry a divorcee is because his job is to increase peace among Jews which includes helping quarreling couples restore peace in their homes. If he is allowed to marry a divorced woman then he might have an interest in NOT making shalom between them so HE can marry this woman [!!].
That reminds me of what one sefer suggests that a Kohen Gadol may only marry a besulah because otherwise he might go into the Kodesh Kedoshim on Yom Kippur and pray that Ploni with the attractive wife die so that he can have her for himself [!!!].
We must be VERY wary of human nature when it is left unfettered.
As the Navi put it ['ירמיהו י"ז ח]:
עָקֹ֥ב הַלֵּ֛ב מִכֹּ֖ל וְאָנֻ֣שׁ ה֑וּא מִ֖י יֵדָעֶֽנּוּ׃
Most devious is the heart; It is perverse—who can fathom it?
