Sudden loss of partner

Hi, I’m new to this forum. I lost my partner in May 2025, he was only 39 years old, we have been together since high school, for 21 years. We lived together for 18 years, trying to start a family, so many plans for the future. He died suddenly, fell down the stairs and that was it. I went to visit my family in another country for a few days, I haven’t seen them for 6 years. Me and my partner were on the phone every day, but on one day he wouldn’t pick up his phone. I looked at cctv camera a home and noticed he is in the floor and not moving. I rang my neighbour and asked her to call an ambulance immediately because I think he is heart. I was looking at him over the camera, both of our dogs next to him Ambulance arrived and I told them I can see them, after less then a minute they said we are very sorry but he has been dead for a while. My heart stopped, I couldn’t it and I felt like in a movie. It has been over 4 months and I feel incredibly guilty for not being there with him, I should’ve go to see my family. I also worry about him, keep thinking where is he, my mind and heart constantly searching for him. I’m still in denial, tried therapy but they were focusing on depression and low mood, wasn’t helpful at all. Apologies for this long post, and thank you for reading. I miss him so much I would give everything just to have him even for 5 min again