I have just went through something similar, was with a guy for 4 months when I found out I was pregnant, he was all happy to start with then started pulling away, blowing hot and cold etc. I knew something wasn’t right and broke up with him – he then showed his true colours.
He sounds like a very negative impact on your life. You can and will be able to do this alone, don’t doubt yourself for a minute. Your kids will get all the love and support they need from you.
If you need support you have everyone on here, I quickly learned this is a great site with very supportive people!
Hope your okay!