Idk what to do

so this past month i’d say I feel like my bf of one year hasn’t been as like flirty and lovey as he used to be. he still is, but it isn’t as much. almost kinda like a chore to talk with me. feel like he doesn’t rlly want to. he sends me cute snaps sometimes of his dog so like I feel like he does still like me but i’m just not feeling very loved. i’m scared to tell him this cuz last time I did he got mad and defensive. so idk what to do. what r some red flags to look out for??