Am i going crazy

Me and my partner been together 5 years and its his ex’s birthday this month and he wants to buy her a gift from HIM. I said i didnt agree with him doing that and he blocked me. Am i over reacting ? Like who the hell buys a gift for there ex.

I have now left him and i have now blocked his number. Aint no woman staying around with a twat like that watching him buy his ex a gift for her birthday. Na. Laters im gone!