Jenih62557 - this may sound picky but the vagina is not a dry dark place.
If a man ejaculates and gets it over his hand and then proceeeds to manually stimulate his partner there is a risk of pregnancy and all the sperm does not die immediately. Same if he ejaculates and doesn't clean up properly and then after a little while proceeds to have sex there is the risk of pregnancy.
You claim to be an ob nurse but remember this is the internet, unless you can prove this and are willing to take the consequences of your claims - you should always err on the side of caution.
See there are enough medical books out there that I could easily pass myself off as a qualified gyno/ob on the internet but I am not and would not - it would be far too dangerous to any people to may read and take to heart my misinformation.
You may well be genuine but please, please err on the side of caution.
If you have seen the patient and are sure of their circumstance that is one thing, but you do not know the full story behind the posters query here.