@TheBrazies, what a blow this must be. After seeing your thread about names for your twins, reading this was quite jarring.
Your H is indeed cheating and abusing your trust. While you’re carrying his twins and parenting his two young children, he’s been busy investing emotionally and sexually in this colleague. She’s his secret. They’ve built an affectionate connection, and he has taped/sent this video to her to show her significance to him. If they aren’t already having video sessions or having sex, he absolutely wants to.
In the minute chance the video is for his own use, it shows his obsession with OW, which throws a grenade in your marriage and family. Either way, I wouldn’t tolerate this betrayal. After viewing his wanking while moaning her name, I’d have permanent mistrust and ick.
If his transgression isn’t a dealbreaker, I’d probably investigate his phone for a few days, keeping in mind that they may be cautious to not be outing in their messaging. I wouldn’t wait too long to confront him about the video. Say, “Tell me about you and Colleague, and any lies or later drip feeding will be the death knell for our marriage,” and then be silent.
Please don’t blame yourself or allow him to blame your diminished libido, his stress, or any other sorry excuse for his unethical, destructive choices. He and only he is responsible for protecting his fidelity, and he has failed.
@TheBrazies, I would send him away while you seriously consider your options. He needs to feel the loss of you and understand what he has so cavalierly risked. I wouldn’t even consider staying with him until he comes clean, cuts contact with OW, provides transparency with devices, and moves mountains to rebuild your trust.
That he is capable of such deception and faithless behavior while you’re so vulnerable does not bode well for the future.