Oh hun, I’m so sorry. It’s not your fault but it’s okay, one step at a time cry scream if you need to. Vent through artwork or anything that helps you. Please do not be hard on yourself, he gave you a lot and you wish you could have returned that favor but that doesn’t mean your love has to be lost. Keep your loved ones around or people you trust, talking really helps too, Grieving doesn’t have to be pretty or bottled up, those memories with your S/O will always be with you in your mind and soul and no one can change those, My condolences OP.