so long story short, my husband I had a threesome the other day (26th January) with another female. We had all had a couple of drinks and my husband ended up coming in her. i am really worried she may be pregnant as we have been trying for years now and are about to go through IVF in a few weeks.

She is on the pill and says that she takes it regularly and also took the morning after pill the next day (not sure what type exactly). she had her last period on the 17th of January, 9 days before hand and says she is due for ovulation roughly on the 31st.

As she is on regular BC and took the morning after pill, I know there will be like a 1% chance but should i be overly worried about the possibility of her being pregnant?