My husband and I fell off the past 2 months 😢

I’ve been so depressed so the past 2 months we argued so much about stupid shit and because I found out he was talking to girls and then one night he came home super late but this isn’t like him at all he just completely changed on me and the past week he’s been staying at his sisters house we have been together for 9 years and never slept alone until now I haven’t slept in 3 days! I’m going crazy I’m in so much pain I haven’t ate in 3 days I have no appetite I’m so sick to my stomach Idk what to do please give me advice to save my marriage