Is he cheating 😔

Hello so I’m married have been for about 5 years we have two daughters ages 2,1 at the beginning of our marriage we were good but lately we argue for anything and everything and recently he made a comment about me getting fatter and then he made the comment of wanting to get a “second” opinion on his penis size since I say he is pretty big but he doesn’t want to believe me all of a sudden he said he would want to know if I’m ok with him getting another women’s opinion m.. do you think he is cheating?