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.
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.
After my m/c (and D&C) I had no bleeding. Everyone is different.