After the begin of the war, when the first casualties reports of the Poland campaign came in, Himmler issued an internal order to the SS and Police. (Although being an "order" it was more like a memo) The order explained that due the nature of war men will die, this was nothing bad as they died for a "higher cause". Yet it was a grievance if they did not have childeren before they fall, leaving without a successor and not spreading his "good blood". As the SS saw themself as the elite, not passing on of the superb gens of the members, was a terrible los. So Himmler issued this order to the SS and Police allowing them to have (multiple) relationships (outside marriage) to breed childeren. Futhermore the order looses women and girls of "good blood" from bourgeois morals, allowing relationships outside of marriages for the purpose of having childeren. The last part of the order aimed at soldiers that dont plan to have childeren till war end to not burden thier brides when they fall. Himmler ensures that every child, legitimate or illegitimate, of a fallen german soldier will be cared for and finacially supported and of the duration of the war the pregnant women and thier childeren will be support if help is needed. The order was a carte blanche for the SS-men and was also used by some, Himmler himself used it to justify his affiar with his secretary. However the order came under large criticism, from inside and outside of the SS. Many people saw it as immoral and for his peers in the Nazi elite it was evidence of Himmler being crazy or ridiculed for expanding his hobby as chickenbreeder on the SS, even Hitler himself was displeased by it. In the SS, especially the officer corps, was very unpopular. There was not so much problem with immorality as many of unmarried lower ranks made use of it. The problem was more that also the wives of the SS-men/soldiers were "free game" now. No soldier is happy about the idea that another man, that has the luck to stay home, can start a state sanctioned affair with thier wifes while he is fighting and dying at the fronline. Futhermore it showed the SS the "insaneness" of thier (unpopular) leader and made out them a laughing stock. So answering the question, Yes and No, SS soldiers would have sex with deployed regular soldiers wives. Often, depends how you see it, Affiars are common in peace and even more in times of war. Men and women dont see thier partners for long time and have thier "needs" or in climate of fear try to enjoy life as death maybe around the corner. However what see with SS order that the affairs, that might have been tolerated when not publicly exposed, were now state sanctioned and propagated. Although ordered or as guidelines installed, by many (often the married) in the SS the order was unpopular and ignored.

http://www.ns-archiv.de/krieg/zukunft/himmler.php http://www.ubonse.de/ubonse.de/rtf/2008.12.9_himmler_fortpflanzungsbefehl.pdf