I agree. It would appear now that there are actually two items which have evolved in the discussion:
Whether a priest ( as confessor within the context of Confession) can"make" an unfaithful spouse admit to their wife/husband, that they had committed adultery.
Whether the offended spouse has the right to know that their husband/wife has been unfaithful to their covenant.
By and large, the answer to the first point is, invariably, “no” ; and to the second point, invariably “yes.”
The rest is simply speculation as to how much additional damage/hurt might be inflicted by revealing the infidelity to the faithful spouse.
Several other points to consider:
The Church does not see adultery as grounds for an annulment - a short article on that HERE.
Concerning the cleaning out and healing of the wound which @Greenfields mentions :With God’s grace human beings are able to rise above and go beyond their limitations ; are able to forgive that which may initially appear to be unforgivable ; are able to say as our Blessed Lord did, “Father, forgive them” - and to mean it.
An extreme example of how God’s mercy and extraordinary graces to forgive are sometimes bestowed/poured out, can be found in the account concerning St. Maria Goretti and her offender. It is a difficult read in spots, but a great reminder of to just what extents humans can go to in terms of forgiveness, when we cooperate with God’s grace. A Story of Great Mercy: St. Maria Goretti & Alessandro Serenelli