I think unless your waters are ready to break anyway or they are very thin (the membranes surrounding the fluid) then sex wont cause them to break. Maybe speed it up if your already dilated abit and they were not far from breaking anyway and sometimes the membranes are buldging through the cervix in which case sex could rupture them. If its has caused them to rupture I am sure its a coincidence or ?bad/good timing and that they were going to shortly anyway.

There would be no way for a midwife or dr to be able to tell your have DTD without asking (or checking with a microscope which we don't do) often vaginal fluid, membranes and the stringy bits you often see in the amniotic fluid are the same texture and colour as semen even when women have not DTD so there would be no questions asked.