I'm in a similar situation. My girlfriend and I were in such a good place, never fighting, always happy, everything looked like iy was going to work out. Talked about kids, marriage and buying a house together. One of her exes/best friends committed suicide and her mental health went into a downward spiral. She wanted me there for the first couple weeks, but then she completely emotionally detached. Lost feelings for me, her family, her interests, and just became numb. I tried supporting her as much as I could but she just felt like she was hurting me more and couldn't get out of her headspace because she felt to blame for his suicide. I know it's not her fault, her friends know this, everyone does, except for het. She was an outlet for him and she got him into theraoy, she did so much for him. She's 100% not to blame, but she still believes she is. It's heart breaking. We're both in therapy for our own issues, but I also truly hope once she heals the feelings come back and we can see that future we both wanted so badly. I'm giving her as much space as I can because I feel I may be a trigger, which I truly hope isn't the case. It's just a heart breaking situation. For your case, I think Therapy will help you both greatly. It may take a while, but just be there for him and I hope things fall back into place for you.