What the frig does this guy think when he has friggin "equity" in a woman...people aren't like a house. This guy is a relationship hopper and used you as an emotional crutch to get over his problems he had with his ex. Next time, if a guy says he's involved with another woman in any way, drop him like a hat. Female friends are fine, roommates are another, but he was supporting her. A guy only does this if they have an inappropriate attachment to her who's trying to get into another relationship.
Stay no contact for sure. State that you don't want him to contact you anymore and if he does then tell him you'll call the police for harassment. And do it if he contacts you again. You don't need anymore of his BS.
He's still online saying he's looking for marriage because he's finding it hard to move on from his ex. He's looking for someone to help him move on from her to lessen the blow. In other words, he's trying to use women for his own benefit and doesn't care about their feelings. Only his own.
It hurts because he baited you to develop feelings for him, probably because he was trying to act nice towards you, so he could use you to get over his ex. He was leading you on and you followed him. Next time, don't get emotionally involved with someone who is emotionally involved with someone else. Because emotionally unavailable people will only end up hurting you. Look for the signs, as it was clear at the beginning of your involvement with him.