My H just separated from me. He's 31, I'm 44. I believe he's in a MLC too but I'll share his behaviors and you can see how it matches up. He married me 5 yrs ago. I have two kids, now D15 and S17. Never wanted kids but was great with mine. We used to do more things together, skiing, mnt biking, etc. With the kids in HS now, their activities have taken a lot of time and I didn't appreciate or spend time with H like I should have. He's been more distant the last couple months and last month announced he was going to our family's cabin to think. One month later, he's still there and says he "can't be with me", feels stuck and just wants to be alone. Feels he had to grow up early in life and now feels too much responsibility.
Maybe some differences to your sitch, but I would encourage you to do the 180 and just back off for awhile. Let H see how you're getting on with life (GAL) and what he's missing.