Why don’t men get it?

So I’ve been in a relationship for 2 years never have given him a reason to believe I’m being unfaithful yet out of the blue yesterday he decided to accuse me of cheating, he does know I’ve gone through that before I wouldn’t do that to someone, so I broke down and wondered off to my sons room to look at him and remember I’ve got to be strong for him now, my partner come in and apologised said he’s wrong etc gone to work today and started again, now girls if I’ve never gone out without him or given him a reason to believe I’ve cheated would you say he’s acting suspicious?😭 he doesn’t have a clue that it’s making me feel so crappy.