Is expiation obligatory for emphatic oaths – such as "Eating you is forbidden to me, drinking you is forbidden to me, your bed is forbidden to me" – that were sworn to a wife with the aim of stopping problems, and should it be before or after retracting the oath?

If you did not intend divorce by the phrase "intercourse with you is forbidden to me," then its ruling is that of an oath, and you must offer an expiation for an oath. If you swore multiple oaths concerning different matters, then broke all of them before offering expiation for them, the majority of scholars hold that an expiation is due for each oath, while some consider only one expiation to be due. The expiation for an oath is valid whether offered before or after breaking it.