RELATIONSHIP ADIVCE PLEASE

Please please please read and help a girl out xx

so recently one of my close friends broke up with her boyfriend of quite a long time. They were pretty serious and they were always the couple that people would say would grow old together and all they stuff - long story short they were pretty tight and no one suspected a break up. I don’t know specifically what it was over but ik there were problems with trust and other girls/guys etc, and losing feelings in general. It just got me thinking about my relationship and I thought I’d message my boyfriend. I messaged him saying “i need to ask you something”. Then I just said “if you ever lost feelings for me do you promise to just tell me” and yeah replied “yeah xx”. Like I just feel really upset about it. I know he said he’d tell me and that’s a good thing but is it bad of me to want a little more reassurance. Like “yeah, but that isn’t going to happen” something like that. I’m not saying I expect to get married and live happily ever after I know how to be realistic but I like being all cheesy and cute sometimes even if I know it’s not realistic. It just seems like he basically is planning to lose feelings and we’re in a really good place at the moment so now I’m just overthinking. Like “yeah babe I’ll be sure to tell you as soon as I lose feelings because it’s bound to happen you know HAHA”. Then I said “and even if you were really mad at me you would talk to me instead of doing something stupid like cheating” and all he replied to that was “wdym talk to you”. LIKE he didn’t even reassure me about U KNOW “I wouldn’t cheat on you” UGH SOMEONE PLEASE TELL ME THEY GET WHERE IM COMING FROM OR IF IM OVERREACTING AND GOING INSANE.