You meet someone new, a friend or a partner, and after a few good conversations you are already waiting for their messages. When they take longer to answer, you check your phone all afternoon and go over what you might have said wrong. You start adjusting what you say so they stay interested, and you agree to plans you don't want so they won't leave you.
Where the fear of being left starts
Attachment grows out of a fear of losing someone, and that fear usually began long before you met this person. For many people it goes back to childhood, to love that came with conditions. A child who is praised for being good, quiet and helpful, and who meets coldness or punishment for being loud, angry or needy, learns that love depends on behaving a certain way. Love becomes something that can be taken away, and the child learns to obey in order to keep it.
Children can also feel abandoned when nobody meant to leave them. When a parent dies, works all the time, or is at home but unavailable, a child can take it as being left. That image stays fixed inside, even once the child grows up and understands what really happened.
What was learned that early keeps acting for the rest of a life. When a situation looks like the old one, the same fear fires again, and you defend yourself the way you learned to back then. So when someone new comes close, the old fear of being left wakes up with them.
Some of that fear may come from even before this life. The brain only holds what happened in this life, but the spirit keeps everything lived in other incarnations: the scenes, the sensations, the emotions and the thoughts. When a situation now resembles one that ended badly, that memory can return as a fear you can't explain. If being left was one of those situations, you can carry the fear of it before anyone has given you a reason.
Leaving yourself to keep someone
To avoid being left, you start giving yourself up. You become what each person seems to want: easy-going with one, useful to another, always available to a third. You make your choices for their approval, and you let them make decisions that were yours. Over time you lose track of what you want, because so much of what you do is arranged around keeping someone close.
This is called self-abandonment. It happens in the hope of finding an ideal relationship, one where you will finally be safe from being left, and it costs you your freedom to be who you are.
Like attracts like
What you carry inside is also what you draw towards you. When you have abandoned yourself, you live in the frequency of abandonment, and the people who come close tend to answer it: they leave, they keep their distance, or they never quite choose you.
Rejection works the same way. A person who rejects parts of themselves keeps meeting people who seem to reject them, and each rejection feels like proof of what they already believed. What you feel about yourself in a relationship shapes the relationship you attract. If, deep down, you feel you are only someone to be with for a while, that is the kind of relationship that finds you.
What changes when you stop abandoning yourself
The first change is to stop leaving yourself behind to keep someone. You don't have to earn love by being good, useful or easy to be around. You can be loved on the days you get everything wrong, and the first person who has to love you on those days is you.
Like attracts like here too. When you stop abandoning and rejecting yourself, you open up to people who have themselves together: people who respect themselves and, by frequency, also respect you and the relationship.
If you want to tell whether what you feel for someone is love or attachment, the difference between the two is worth reading next. And What's Blocking Your Natural Flow? can give you a first sense of what may be in the way for you: it's free, it takes two minutes and you get your result right away.