He told me....need advice

Da

To start, i have never ever cheated on a significant other and ive been cheated on. So my last relationship was mentally/emotionally abusive and that ended in May. So this summer i went on a dating app & met someone who kept wanting to hangout, messaging all the time. So one night i said screw it, I’m going to go. And we hit it off.. it did become sexual very fast but it was passionate and we started seeing each other sooo often. He started calling everyday and calling me babe and boo. We had to see each other all the time. He would take me to fancy restaurants on dates & movies and it wasn’t just sex. We talked about everything from family to work.

One day we go to the bar && he admits he has a Girlfriend!!!! And not only that.. he LIVES WITH HER.

So i never went to his apartment because he said his sister is living there temporarily. I was SO stupid to fall for that. And the problem is i even had a heart to heart with him where i told him about my past relationship and how i really am damaged and trying to heal.. and i can’t get hurt anymore. And he didn’t even tell me about the gf at that point. He said “i am here for u and only u”. Bullshit lies:( i am so upset but attached to him. I get attached because he was everything i was looking for. I thought it was a real connection. He always talks about our future..He continues to tell me he will leave her soon he’s figuring things out. I don’t think he will. So i need advice on what to do. Should i tell his gf? Should i just ghost him?