I’ve never dealt with this before

No one has treated me like my recent ex of 3 days, I’ve only been used to abuse that gave me easy reasons to leave. I feel so alone and un-whole. I don’t know who I am without him and I know that’s the problem. I feel like I must be loved to be seen. I just want to be able to see myself but I don’t know how. Please give me any kinds of words of advice.