So me and my partner split due to us not getting on as well and his parents not liking me and making his life hell for it. I was still living in the property with our two 12 month olds and we were actually starting to get on better again and we were getting on like nothing had changed. A month later we were going away for the girls birthday and he just seemed really off all of a sudden, like he seemed quite nasty towards me and cold. He was on his phone a lot which I found odd. We had a few arguments whilst we were away because of the way he was talking to me. He kept saying "You're getting on my nerves" when I was literally doing nothing. He said in an outburst of rage "I don't love you anymore, I don't care about you and you're not my problem anymore" but later apologised and said he didn't mean all of it. I asked if we could try again and he said he'd need time to think about it but thought it was past fixable now. When we got home we were getting on really well again and spent a lot of time together. I asked the question if he had thought about trying again and he said he still needed time to think but it wasn't a no. But he was still constantly texting. I asked him if he was texting anyone else and if he was could he please tell me the truth so I could move on. He repeatedly said no. Something just didn't feel right, I know I shouldn't of but I looked on his phone for my own mental health and reassurance..he was infact lying and sleeping with a woman from work. When I confronted him his reply was "So I don't care, it's none of your business" two days later I left and went to stay with my mum. I've been here for 3 weeks. He comes to visit the girls once a week whilst we make a parent plan for him to have them more regularly.
My question is, how do you co parent when you're heartbroken and absolutely gutted? We got on really well before all of this and had a really good relationship. I never wanted my girls to have two different lifes and I'm so upset about it. Every time I see him and I just feel rubbish and heartbroken all over again.