I’m not sure if those text prove sex. At a trial I’m sure his lawyer will say they were joking around.
His other girl friend said that they had sex at his home in his wife's bed.
Regardless, screwing around with a military man's wife, whether your are boffing or just talking about boffing is verboten.
I was not married during my time in the Army, and I was not an officer, so my boffing officer's wives meant that if I got caught I'd only get shot two or three times:)