Mother’s Day issue

So I thought I’d do some browsing and try and get other peoples opinions on this. My fiancee decided to buy flowers which were (red roses) from his kids. I want a fan at all and it actually pissed me off. There are deeper reason why it does as in the past she has caused such a headache for us including at my workplace. This individual in the past has gone to the point of stalking him and I.. saying negative things about me to her own children which she still does to this day as she’s extremely jealous. People at my workplace where she also works says the same thing. When him and I first met she had the guts to tell people at my workplace(where she worked also).. that they were still together and that he was having an affair on me(which wasn’t the case at all).. as when her and I had words over phone she denied it all and was trying to deflect everything. there’s a lot more but my point to him.. why would you go and buy her flowers specially red roses from your kids when she has caused soooo many problems for us. Am I crazy for thinking this way by getting upset about it? I mean I told him he could have just got a gift card with a card.