Therefore, semen like any other najis things is haram (forbidden) for the wife or anyone other than her to swallow.
In any case, the answer given by Ayatollah Mahdi Hadavi Tehrani (may Allah grant him long life) to the second part of the question is as under:
 - Tawzih al-Masail (with annotation by Imam Khomeini), vol.1, p. 69, issue No. 87.
 - Ibid, p. 94, issue No. 141.