They are who they are, and they will treat people pretty much the same across the board. If you give them the responsibility of your self-worth, they may treat it well or they may stomp all over it. Or they may seem to boost it at first, then stomp all over it.
The thing to learn after someone's really crushed your self-worth is that you should always keep it and hang on to it. If you accept yourself, and you're always doing your best, while still allowing yourself to be human and make mistakes, then your self-worth should be very solid.
When you love, you keep the validation of your worth in your own hands. If they treat you well, then it's a match to your own level of self-worth. If they don't treat you well, then it would not crush your self-worth, but instead would make you realize that they're not willing or not able to treat you as well as you deserve to be treated.
A relationship like this may come to an end sooner, but it would do so with a feeling of "that's really too bad. I liked that person a lot." and moving on...not trying to convince them that you are worth more than you're being treated, and not trying to "kill them with kindness" or prove your worth to them. If they don't see it, or if they do see it but just have some things going on within themselves that prevents them from treating anyone well (including themselves), then they are not in a place to be a good partner.
They may need a friend, or they may just need some more years to figure themselves out, but trying to be in a relationship with someone while they're at that point will erode or even completely wreck self-worth.
To show love for the self and for the other person would be to let the idea of a relationship now with them go. You'll end up saving them regret of not treating you right down the line as well. No one really wants to treat anyone badly, but if they have their own insecurities to battle with, it's just going to happen.
You can love openly and fully, while holding on to your self-worth. When someone comes along who sees in you the same things you do, it will be true love, and it will be incredible. So work on rebuilding your self-worth...become aware of negative or limiting beliefs you've taken on, and let them all go. It's a process, and it may take awhile, but it's completely worth it.
By doing so, you will realize every great thing about yourself and know that you don't need to fear anything about any other relationship from now on. No one will be able to take your self-worth again, not because you'd become cold or closed off, but because you will see your own value, regardless of if someone else does, too or not.
By Doe Zantamata