Why am I not good enough?

This might be all over the place so excuse me but I need to let it out. My ex and I were working on getting back together. We’d been through a lot during the time we weren’t together including the loss of one of his parents so after this occurred he said he didn’t want a relationship but would often want to do relationship things with me, as time went on he would say he didn’t think I was putting forth efforts when I literally did everything I could to be supportive, and show that I care. I made time for him although both our work schedules are busy, I’d inquire about his day, encourage him when he’d hit a very rough patch in his grieving stage and an abundance of other things. During this time his effort started to decrease and he’d say he was just busy from work and I was the one who wasn’t trying. Two weeks ago he said he just wants to be friends and now he has a new girl he’s talking to. My feelings are crushed and I feel as if I’ve been used and abandoned. I just want to know why my efforts weren’t good enough? Am I not enough ? I know I’m a wonderful girl with an amazing personality and big heart but I just can’t shake the feeling of being ugly and abandoned.