@heartbroken26 oh op. This is just horrible. It sounds like your friend knows her sister and since she's said she's not sure she believes her I would tend to believe your friend over this women (who clearly has the morals of a alley cat)
I don't know if sharing my story would help, but I found out my (now exh) had a affair after our boy was born still. My fault apparently for not being up for it... I was"mopey" 🙄. My friend told me, I had no idea. It was hideous - really hideous but fast forward many years he has married the Ow and to be fair to her she's a excellent sm to my Dd (words I truly thought I would never say) limited interaction. For a long long while I was angry but I realised that actually mostly I was angry at him because he broke our marriage vows and couldn't even take responsibility for what he did. He blamed me. Coward.
Obviously these women don't owe us anything but I have to say I think I was more angry at her because I still loved him(at the time) now tbh I'm passionately disinterested in him bar our child, and I had what I can now say a lucky escape and I'm happily married to DH and had another baby.
Your situation is a bit different as OW sounds deranged (who lies about a pregnancy?!?) but sounds like he deserves what he gets with her. What goes around comes around.
Re finances are you Mortage or rent ? Do you know what he earns (keep copies or make copies of pay slips) entitled to should help. On your own I believe you should get some support.
I just want to give you a cuddle. I know it feels like your drowning right now, but you will get stronger, you will learn to swim and hopefully your ex will be bitten by a shark (tongue in cheek kinda)
This wasn't about you or even the ow. This man is broken. That's why he did this. Whatever you decide I hope you find peace 💐💐💐
How you coping ?