Love him but hard time forgiving

Almost a year ago my boyfriend and I were going through a really rough spot and he met someone else and left me for her. It hurt a lot as we dated for 2 years prior to that. I got into a new relationship after he left me but I decided to end that one as well. He came back about a month ago and told me that he had made a mistake and that he’s loved me this whole time and he regrets his relationship with her. I want to believe him because I do love him as well but I don’t understand why he didn’t come back earlier if he loved me the whole time (he dated her for 7 months and said he was scared I hated him and didn’t want to hurt me more so he didnt want to contact me) I want this relationship to work but I’m have a very very hard time forgiving him and I don’t know how. I’m still hurt over everything and it’s all coming back to me again.

I don’t need anyone telling me to leave him I just need advice because I love him but I can’t seem to get over this