does he deserve a gift? 🤔

Sorry for the long post.
Sooo, i found out that my SO called her ex, they were together for a longgg time. When i found out i txted him asking why he was still calling his ex & that i was looking stupid while i was home all day taking care of the kids & he was out calling his ex ( he was working that day). But he never replied to me, when he got home, i was like so when are you going to leave? & he was like whenever, so i was like okay then, leave now & he was like yeah yeah okay. Soo eventually i had to ask him why he called his ex .. again! & he said just to ask about one of their mutual friends because his friends dad is sick & my SO wanted to know if he was okay. But im like you really had to call her? 😒 & he didnt respond.. I mean i feel like hes saying the truth because he doesnt look guilty at all, i think he just gets mad the way i handle things sometimes but they were on the phone for 18 mins 😒. & i cant help to not be mad because i know that if he ever sees me talking to my ex or other dudes he would get mad. & this happend on monday & im still mad at him & idont think he deserves a gift this christmas for what he has done all year. Because sadly this is not the first time i find him doing some sneaky stuff 😒. Any advice? Should i just let it go? 
& btw last christmas he didnt even bother to give me a gift & i did gave him one lol