After my m/c (and D&C) I had no bleeding. Everyone is different.
Mc's can last for more than a week and your cervix are probably still tender and the intercourse could have just irritated the cervix some.
sorry about your miscarriage. How far along were you when it happened? When I miscarried both times, I only bled heavy for 2 or 3 days then it tapered to almost nothing the last 2 days. Some women bleed longer and others don't.