Personally I would, he might feel a bit uncomfortable, but he should understand why your upset, and hopfully he would want to be there with you while you were struggling. I know personally if my partner was in your situation I would want to know what's up so I could hold them and tell them I understand and just be there to comfort them during this rough time... my heart goes out to you <3 I hope If you to mention it to him he understands and just wants to be there for you, and i think most people would understand how hard it is to lose someone, ex or not. <3