Disgusted in myself... (exboyfriend)💔

So my ex boyfriend and I started talking again around the beginning of December of 2015. On January 18th, it's going to be him & his girlfriend's one year anniversary. Since we broke up November of 2014 I haven't moved on since. I'm so so in love with him. So for him to message me relieved a lot of my depression... until something happened. So, after a while of talking he became sexual with me & we sexted eachother. And he would always message me in a flirting way, called me to say he loves me, and talking dirty. I didn't want to be sexual, I kept saying "no, it isn't right", "you have a girlfriend, leave me alone", "i just want to be friends, nothing more." I guess he never got the message. So today, I got a phone call from his girlfriend off of his phone saying that I "better stay the fuck away from her boyfriend, and if I have a problem I can meet her somewhere" (talk about trashy!). So I texted him, flipping out on him, basically saying that I never want to hear from him again, and I do love him so much, but I need to stop thinking about other people's feeings all the time. That's my problem. I never worry about my own happiness... maybe that's why I'm depressed. I was probably used just for his pleasure. When we sexted, sometimes we'd video chat naked & do stuff, he'd always cum, but I never got anything out of it. I actually felt rather uncomfortable. So today I messaged his girlfriend telling her that she's stupid for dating someone who is unloyal and does shit with other girls behind her back. I said some rude stuff as well that I wish I could regret, but she's said much worse to me so I don't feel bad. Do you guys think I did something wrong? Was I helping him cheat on his girlfriend? Oh lord, I feel like a filthy pig. 😭 Please be honest, even if it's criticism.Â