Help

Just give him some personal space without any social interaction from you or anyone else. I understand that you don't want to lose him, but if you keep interacting with him, you will only push him further into isolation. He needs a lot of personal space to himself, to recharge his drained batteries, and to do the interests that he likes doing, and it's what he needs that to be healthy and stable. 

If you try to distract him from his interest, it's like when someone tries to wake you up in the middle of the night, and you only had one hour of sleep, you had a very long stressful day at work and you're extremely tired and agitated, and you just really, really need some sleep. You won't want to socialize or talk to anyone, you just want some sleep. That's what you know that you need to be happy and healthy. But then someone keeps trying to distract you and keep bothering you to wake up, because they really want to talk to you, but the only thing you want to do is sleep, it'll drive you crazy. 

However, understandably for you, this social withdrawal phase  that your husband goes through creates a fear of abandonment, that he's "fading away" from you, so you in response to that you try to socialize with him more, engage with him more, "what can I say and do to get him back?" so that you don't lose him. But socialization is the very thing that drains him and that he's trying to get away from, which is why he's withdrawing in the first place. 

Typically you think there is something bad going on when someone doesn't want to talk to you or interact with you, but this is not the case. Everyone needs personal space from time to time, but your husband needs a lot more personal space than the typical person would, and by a lot I mean a lot. So even if it's counter-intuitive and against your nature, ignore him for a few days, do something else, go outside by yourself somewhere and enjoy the day.  

Just give him some personal space without any social interaction from you or anyone else. I understand that you don't want to lose him, but if you keep interacting with him, you will only push him further into isolation. He needs a lot of personal space to himself, to recharge his drained batteries, and to do the interests that he likes doing, and it's what he needs that to be healthy and stable. 

If you try to distract him from his interest, it's like when someone tries to wake you up in the middle of the night, and you only had one hour of sleep, you had a very long stressful day at work and you're extremely tired and agitated, and you just really, really need some sleep. You won't want to socialize or talk to anyone, you just want some sleep. That's what you know that you need to be happy and healthy. But then someone keeps trying to distract you and keep bothering you to wake up, because they really want to talk to you, but the only thing you want to do is sleep, it'll drive you crazy. 

However, understandably for you, this social withdrawal phase  that your husband goes through creates a fear of abandonment, that he's "fading away" from you, so you in response to that you try to socialize with him more, engage with him more, "what can I say and do to get him back?" so that you don't lose him. But socialization is the very thing that drains him and that he's trying to get away from, which is why he's withdrawing in the first place. 

Typically you think there is something bad going on when someone doesn't want to talk to you or interact with you, but this is not the case. Everyone needs personal space from time to time, but your husband needs a lot more personal space than the typical person would, and by a lot I mean a lot. So even if it's counter-intuitive and against your nature, ignore him for a few days, do something else, go outside by yourself somewhere and enjoy the day.