My husband doesn’t trust me, what should I do?

So my husband and I got married 4 months ago. Sometime last month he looked through my phone (which is not a big deal, we are open with our phones) and started asking about my boss at work. He called me to discuss something that was going on. I work off site and see him about once every 2 weeks for a meeting with 4 other people. I explained all of this to my husband and he seemed upset. He asked how old he is. He is only a couple years older than us. And he went on about how he doesn’t like this guy and that he could call me whenever. I told him I had called him one time which is true for about ten minutes. And that was that. Well it’s about a month later and I have a group message about PTO and we let him know if we have time off for holidays and I discovered my husband had blocked his number. And now I think I need to ask him about it but I’m afraid he is going to blow up. Should I let it go and not say anything or try to bring it up and cause a big fight?