suffering from postpartum depression

I’m 25 and a mom of 4 little ones. Ages 8,6,3 & 4 weeks. I’ve never had ppd before but I feel like I definitely have it now. I literally have to drag myself out of bed when I haven’t slept in weeks and I feel like my whole entire world is falling apart. when I was 37 weeks pregnant I caught my husband texting another woman & then he told me he wanted a divorce that he wasn’t here emotionally anymore & that he loved me but wasn’t in love with me, we have been together for almost 9 years. In 2017 he left me and his children because he needed time to find his self but ended up with another woman living with her & getting her pregnant, they didn’t work out he left her & she terminated the pregnancy she was 22 weeks I believe. he then decided to start trying to hang it with me and his children again & because all I ever wanted was for us to get along and be there for our children I let him. he told me that he still loved us, a month later his mom passed away & his grandmother passed a few weeks later. after that he said he needed us, we were the only family he had, and that he couldn’t imagine being without us. things were going perfect, we were taking family trips just all out having fun and our relationship was the best it had ever been or so I thought. but he started acting different & his behavior started changing. he was being so defensive about small stuff, but that night I addressed him talking to another woman he informed me that he hadn’t been happy, he was trying to be with me to appease his family and mine. even though we were literally just trying to plan another wedding for our 10 year anniversary. now he’s saying he needs time to work on his self, he has to find himself and what makes him happy, even though he’s on tinder & going out on dates with other women. how do you find yourself in other women ? . I’ve moved back in with my mom & im just a wreck, I can’t get out of bed some days most nights I cry myself to sleep. I never planned on being a single mom of 4 kids I finally thought he had really got it together and now I’m stuck with 4 kids and no income while he’s at our apartment that we just moved into living his beat life going out to strip clubs & he’s barely seen his children. I’m trying to be strong for my children but I have random times I’ll get really sad and just start crying and they don’t know why. trying to hold it all together when I’m falling apart is so hard.