I'm not going to rule out the marriage being an impulsive decision...but...could the person JM married have some knowledge of what happened (having been told by JM), so marriage, rather than living together, would give him an acceptable reason not to testify against his wife?
JMO
I had never even thought about that and now I wonder about it. I also wonder if Idaho had common law marriage rules and maybe the father could be considered married at the time he was with her. So there is a real possibility that strategic marriage was done for a reason. It could be protecting the previous father and now the new married folks.
Ive been reading about it and it sounds like there are two different privileges. A communications privilege and a testimonial privilege.
Under the testimonial privilege we see this
"The witness-spouse may invoke testimonial privilege regarding events which occurred (1) during the marriage, if the spouses are still married; and (2) prior to the marriage if he is married to his spouse in court proceedings at the time of trial."
So under number 2 that seems to apply to the two married people.
And then under the communications privilege and if common law marriage is valid in Idaho then we see this
"Unlike testimonial privilege, the communications privilege survives the end of a marriage, and may be asserted by a spouse to protect confidential communications that were made during the marriage—even after divorce or death."
"The spousal communications privilege or confidences privilege is a form of privileged communication that protects the contents of confidential communications between spouses during their marriage from testimonial disclosure."
https://en.wikipedia.org/wiki/Spousal_privilege
This could possibly protect the bio father and her if common law marriage rules apply in Idaho.
I am sure lawyers would end up arguing things in front of a judge about the admissibility of the privilege but it does sound like there is a chance that the new marriage may have been a strategic ploy.