It's a rough day

A few years back, my fiance was engaged to a girl, we'll call her Courtney, who had epilepsy. Courtney died because she had a seizure, fell out and hit the base of her skull on a counter top causing her brain stem to separate. Today is her birthday, and she died on his brothers birthday. My fiancé feels like it's his fault and it wouldn't have happened if he had picked her up like he was supposed to on his brothers birthday (which is next week), but his brother asked him to hangout instead. 
I'm having to support him today, when in all honesty, I don't want to. I feel highly inferior to her. When he talks about her.. I don't feel special at all. I don't want to think about the fact that he was trying to get her pregnant without even having sex with her.. At all they're entire relationship. Or the fact that he never even tried to have sex with her. He loved her so much he would just give her his semen when she asked for it.
But regardless of my feelings, I'm putting them behind me and I'm going to be there for him anyway. I'm not going to make this day, or next week harder on him. I'm just going to be there for him the best I can.