@MidLifeCrisisMama - sorry to hear what an incredibly difficult time you are going through. I am sure you will find some support here. You sound like a very caring mum and your worries about the future are ones that many of us have had to face on this thread.
The thing that jumped out of me from your post is that you say you were struggling financially on maternity leave and had to get into debt to pay your way. Reading between the lines it sounds like your ex was financially abusive. A caring partner would provide for his partner on maternity leave and not watch them struggle. A caring partner would support thier partner in debt and be there so thier partner could talk openly about their worries, financial and otherwise. It sounds like you have done nothing wrong. You did what you had to to get buy and you had no other choice. There is nothing to be sorry for here. It is your ex who was in the wrong.
It May feel awful and overwhelming now. But it sounds like you have had a lucky escape. It’s an awful life to be trapped with someone who does not appreciate or care for you, or make you feel valued and loved and supported. It’s lonely and demoralizing and you loose yourself. You sound like you have probably done all the hard work in your relationship and your ex was lazy- so doing it by yourself, although daunting, will be something you are able to do and used to doing. It may not feel like it now but you will find your strength. It’s there in you and it’s got you this far, you are drawing on it all the time.
It feels hugely Overwhelming, but the awful shock and grief does slowly get better, day by day. It’s an emotional rollercoaster, but the balance will tip and there will be more and more moments when you feel relieved and free and strong. Call on all your friends and family for support if you can. Make sure you have someone you can talk to about this, it helps. Write things down and let your emotions and thoughts out, so they are not going around and around in your head.
You sound worried about finances and how your future will look. It’s really important to see a solicitor. Ask friends for recommendations. Many family law solicitors Will give you a free 30-60 min consultation. Ring around and line up 2 or 3. Prepare any questions you have and see who you like the sound of and who you thing will work for you. Many solicitors offer payment plans for when finances are settled. You can also do most of it yourself if it’s straightforward. But really important to get the correct legal advice re: custody of your child and finances.
Re: you ex and sexting. Try to focus on you. His behaviour sounds cold and uncaring. He has moved on and is looking for self validation from women he doesn’t know. You need to focus on you. There is absolutely nothing you can do about his behaviour. It’s a horrible feeling but he will do what he wants now. You may not feel it but you are strong, draw on your strength. Try your hardest to get rest, enough food to keep going and support where you can. The sense of grief and the overwhelming feelings at this time make this hard but you will be ok in time. Have you got anyone in real life you can be with today? ❤️ 💐