Devastated month

My partner of 22 years, Mark, passed away on May 2nd.  I've been trying to cope, but just when I think I'll be fine for a minute, I keep recalling to when I found him on the garage floor.  His autopsy says cad , the coroner said it was quick and he probably hadn't known it was happening, heart attack.  I am so so sad, I loved him and do love him so much more than anything or anyone ever in the past present and future. How do I cope now?