I’m so sorry Op I’ve been there too!
I was with dp from age 15, when our dd was 2 he disappeared. After logging into his social media I discovered he had been seeing another woman, probably for longer than I first thought.
The worst thing was I had invited her into my home! He brought her along with her “boyfriend” she was heavily pregnant. I later discovered it was dp baby and the boyfriend was just a lie to keep me in the dark!
So the inevitable happened, he moved in with her, never saw our child but played daddy to her other child and their one in the way. I received awful messages from them both, they played happy families on social media etc.
I struggled a lot at first, I barely ate and lost a lot of weight, I spend hours looking online at photos of them, drove myself crazy. I jumped into a few crap relationships, but they didn’t work out.
Eventually I focused on myself, found a better job and genuinely enjoying spending time just me and dd.
A few months passed and the idiot turned up at my doorstep. She had cheated on him and left him, now pregnant with someone else’s baby. I refused to entertain the idea of getting back together.
Fast forward 4 years, I met someone awesome. We had some lovely dates together and slowly did things as a family. We moved in together after 2 years and are now in the process of buying a house together. He really is the loveliest person. I am now 30 and we age trying for a baby very soon ( I had dd age 18).
The reason for my story (sorry about the length) is to show you how things change. If someone would of told me when I was 20 that I would meet someone else, I wouldn’t of believed them. But honestly there are amazing people out there.
Don’t give up op, focus on yourself. You will meet someone else one day, if you want to.
Can I ask how old you are?