I honestly wouldn't even consider leaving if my partner said that they were told I cheated - and could prove they were told.
I guess I don't understand - Are relationships for most people this extremely fragile? (Honest question!) I'll stick with my partner until he is given reasonable doubt of my sincerity by people actively lying and attempting to manipulate him by his insecurities.
People cheat, they don't turn into zombies and biting into necks - they just do. No tell-tale signs if they're smart and at minimum 10% of partners have cheated, the expected rate is a lot higher due to under reporting.
He was told you cheated, people don't go around telling other people that. Friends are a trusted source of information.
What would you honestly had like him to do? Oh your friend told you I cheated but come on sweetheart, like I understand hormonal imbalances and a stressful time could impair my judgement and that a person whom I've been getting along with and see as a good friend as well as a person who lives in the same house as us would be a relatively good choice if hes sending me signals he was okay with it or into me, but come on! It's not also like your friend whom you trust wasn't swearing he saw me making out with him! He's more along the lines just 'saying' he saw us making out.
"Oh, I see honey." "I realize that I must completely trust you above all else, disregard all other forms of trust and fail to recognize any evidence to the contrary!"
or
"I see. I doubt you - I'd like to confirm this fact with other sources of proof. Until then my image of you has been crushed by a trusted confidant and I'll likely have issues tempering my anger of this possible extreme betrayal. So I might be distant, cold, and nasty as a method of controlling my reactions as well as coping, probably fucking balling my eyes out on the side"
Or is it just that he requested proof that his child was his - a very very very strong fear. In terms of insecurities here - we're talking fucking 10/10. He is told from a trusted source you cheated on him with a friend whom he took under his wing, and all the while he puts two and two together and thinks...Oh my fucking god - this kid possibly isn't mine. If she was willing with him under my own roof...
We're talking insecurities that everyone has.
I...You make me hope for a partner that would be open with me and would be open to talking to resolve issues.
I realize my opinion might be against the grain, but...I wish you the best. I know I wouldn't want my mother to stay with my father if he had reasonable doubts to her loyalty from a trusted confidant.
Because being in a relationship means undying faith with complete rejection to all evidence to the contrary. /s