We are in relation from past year and a half. He called me but my mobile was off as my mobile was put to charge. Later when I called him he said I might be talking to someone else so my mobile was off. Now what to do to explain him I wasn't talking to someone else?

My son 26 yes old is like that (not about the talking to ). Just me not answering he flips out that I am ignoring him on purpose. I show him my phone is dead and he will still be mad. I think it shows a lot about their temperament and how they perceive things.

You do nothing until he calms down. Does he always get mad and jump to conclusions over nothing? That's insecure, and immature.

Tell him only once. Do not apologize or over-explain and cry and plead for his forgiveness. Your phone was charging. If he doesn't accept that, ignore him and make samosas or clean out a closet to work off your upset. If he continues to treat you this way and not believe you (and suspect you of cheating on him), it's time to rethink this relationship.