Your husband wants out. He's been quiet and hasn't shared his feelings with you. You're nervous. You're wondering if he is leaving you for someone else.
While it makes sense you are scared out of your mind, don't freak out. If you want him to stay, the best thing to do is give him space. The more you nag, the more he will pull away. It's likely what he has done throughout the marriage.
More inspiration on how to save a marriage when he wants out:
There is usually one person in the marriage who minimizes their energy, (let's call him the Turtle) and one who maximizes her energy (let's call her the Hailstorm).
The Turtle goes into his shell when he doesn't feel safe. The Hailstorm pursues the Turtle when she isn't noticed or seen-which feels incredibly unsafe and scary to her.
While there are plenty of men that are Hailstorms, we typically see men as the Turtle in the relationship.
This means that he learned at a very young age that in order to get his needs met, he needs to withdraw and get small.
If you're a Hailstorm, that probably feels very threatening. And it could be the reason why you have been nagging, loud, and critical.
The problem is, he needs you to tone it down and back off so he can feel safe.
So what you need to do at this point, to get your husband back, is to be a safe and non-threatening presence.
Learn the Mirroring process in the Imago dialogue so that you can make it safe for him to open up and express his feelings without fear of a backlash.
It will make him feel heard and help you understand him better.