This is probably my favorite quote ever because I think it holds so much truth. If you do not think you deserve someone that is good to you, you will not ever be able to accept someone that is good to you. It is so important to be self aware and have self respect. Being in a functional relationship is more than just being in love, it is a partnership. You have to be able to support that other person and grow with them as you build your lives. If you are not comfortable and happy with yourself there is no way you will be able to support someone else and make them happy.
Having a lot of relationships in your life does not mean you are an expert at them. Remember that having a lot of friends or dating a lot of people will not make you feel whole; having quality friends and eventually that one relationship that is just right for you will. People will walk in and out of your life until your dying day. This does not mean that the people that leave are bad people, or that they mean anything less to this world than you or the people that are important to you. I believe that even if someone was only in your life for a moment they made a difference. But not all of those people are meant to stay.
This goes with a bit of what I said in the last point but this is something that I am absolutely struggling with right now. The saying "it's better to have loved and lost" feels like complete crap when you are hurting. Trust me, I get it. The worst part of having your heart broken for me is not being able to even comprehend the pain and how I ended up here. But like I said, take in your experiences and learn from them. You will heal. You will be okay. And you will come out stronger on the other end. I believe that everything that happens in life ties together and everything is meant to work out in the end. If you also think that way (which I hope you do) imagine this- as great as you thought that last person you dated was, even though you are devastated right now, the fact that you broke up means that they were not the right one for you. The same goes for friendship. This means someone else is out there for you, and they are right for you which means that they will treat you better and make you happier than you can even imagine.
Here is a two part because I think the first one is untrue, and the second part is the reason. When things do not go the way we plan with someone we were really close to, it can be pretty devastating. I have heard this a few times recently but I don't think it is true to say you never really know a person. I think you can absolutely know someone to their core, but remember that everyone is subject to change. No one can say that they are the same person they were years before. Honestly, if you can say that you are going about this whole life thing wrong. I said it before and I will say it a million times over, work at the things and the people that are worth it. To make a relationship last you need to learn to grow together. But it takes two and that is the hard part. As much as you may try you can't do it all alone, you need the person that will try as much as you. You deserve someone that is willing to try as much as you. And unfortunately sometimes even if both people try, it still may not work because people change and anything can happen.
This is how we go on: one day at a time, one meal at a time, one pain at a time, one breath at a time. -Stephen King
I have absolute faith in God, and I pray that you do as well or at the least that you have faith/hope in something, even yourself, and that you hold onto that:
"We have this hope as an anchor for the soul, firm and secure" - Hebrews 6:19