I do not mean to shame anyone. Loving yourself is a lot harder than you might think. It requires you to ignore past lies people have spread about you, to embrace every little flaw, and sometimes to even reevaluate the life you're living. The problem with not loving yourself and then jumping into relationships, whether romantic or not, is that if we do not love ourselves how can we expect others to know how to.
To an extent, friends and romantic partners can help us love ourselves more. They can bring out sides of our personality we never knew existed and open our eyes to a new perspective on life. But, in my opinion, I don't think they can plant the seed of love in us. They can help us water it and watch it grow, but they did not start it and it is not their job to stimulate it. We must learn to love ourselves apart from all the friends, family and significant others. If you cannot be happy with yourself when no one is around, then you have placed too much pressure on those close to you.
As a Christian woman, I believe that I am loved by God even in my darkest times. This notion, that even when I do not love myself, He loves me, has kept me going through all the good and the bad. Your friends, your boyfriends and girlfriends, and even your family members are only human. They go through the same struggle of loving themselves and figuring out their own life. To place your security on them is selfish and as I've learned it will crumble in time. They are only human and the weight of your insecurity is too heavy to hold forever. I believe that there is only one being that can support me forever and that is God. If you aren't religious like I am though, we can apply it to ourselves (and I do sometimes as well). We must tell ourselves that we are loved and willing to be loved by others.
A lot of us were taught how to love others from a very small age. The quintessential 'golden rule' rings in my head: "treat others the way you want to be treated". So what happens when we don't treat ourselves in a nice way? We wonder why we sometimes we can't find it in our hearts to treat others justly - it is because we don't do ourselves justice. We fill our heads with self-demeaning and destructive thoughts and then wonder why we can't even look at ourselves in the mirror. Forgive yourself for the mistakes you've made. Stop telling yourself that you aren't good enough, or thin enough, or pretty enough. You just need to believe that you are and not let the world's lies affect you. I'm not saying it's going to be easy. I still struggle with loving myself through it all. But when you truly love yourself, apart from everyone around you, you will be unstoppable and then others will see how to love you too.