Sister lying about baby daddy Update ***Long***

Update on the situation from my 2 previous posts . If you didn’t see them basically my sister is 8 months pregnant she announced it round 5 months but wouldn’t say who the dad was then recently decided to say it was my mans best friend . Long story short probably 8ish months ago they woke up next to each other in bed he was incredibly drunk practically knocked out the night before he asked her in the morning if they had sex she said no , now suddenly 8 months later she’s saying they did . I weirdly had the suspicion that my man was the baby’s dad because of his weird behaviour , in my update I’d finally asked him if he was the Dad and he avoided the question multiple times before he said no . After that I confronted my sister I only asked her if she was lying about who the daddy is , she went psycho telling me she hates me and she hopes I die . Then yesterday my mom calls me and tells me my sister wants to speak to me I thought she was just going to apologise for her crazy outburst so I go there and she’s crying . SHE TOLD ME MY MAN IS THE DAD ! Now for over a week I’ve had this feeling he was but when she said it I didn’t believe her ! I told her to call him in front of me and not tell him I was , at first he sounded confused as to why she’d call him so part of me believed she was lying but then she said that she wants to “tell me the truth” she didn’t say anything specific but he started screaming calling her a whore a bitch saying he’ll kill her if she tells me ! She hung up and he kept calling her back I couldn’t take it I had to go on confront him I told her to answer his call and add me in on conference and I kept the call on whilst I drove to his place he didn’t know I was on the line . He exposed everything they’d had sex more than once whilst me and him were on a break she apparently told him she’d take plan b but she lied he told her he’d pay for an abortion she NEVER SLEPT WITH HIS FRIEND he only wants me and he said some seriously disgusting things to her I won’t even repeat . When I got to his place he was still spouting off at her when I opened the door he was coming down the stairs and he must have realised when he saw me that I knew everything . He threw the phone and ran straight over to me saying “she’s lying” then he started crying his eyes out and clinging on to me . Up until that point I kind of felt numb but then my tears started flowing . I’m so heartbroken . I’ve never loved anyone more than I love him he was my life we only went on a break because we’d become so dependant on each other we needed some space it wasn’t nothing too serious I never felt I had a reason to doubt him I trusted him . I saw so many commenters on here saying if you don’t trust him leave him but I DID trust him but some sort of instinct kicked in and I KNEW something was wrong even though I’d never doubted him before and everyone thought I was crazy . I don’t know what to do I could accept he slept with someone else we wasn’t together at the time so he didn’t cheat but why my sister ? And the lies how can I forgive the lies how am I going to be able to look at my niece knowing what she’s a product of ? I’m just so numb I don’t know what will help me right now 😭 I think I understand the saying ignorance is bliss part of me wishes I never went seeking the truth 💔