<human>: I, about a year ago, was left by my girlfriend of 6 years as she wanted to be single and try to figure out who she is. 

Another girl I dated for a few weeks said the same thing and got lost in her studies (I am still friends with her and this is definitely the case). 

And just tonight, this girl I was dating for the past few months decided she was not ready for a serious relationship because she is afraid of relationships but also wants to focus on her studies, work, acting gig, modeling and all that which essentially takes up all of her time. She said she felt bad because I was not on her mind because of all she has to do and even though she really liked me couldn't even date me any longer and just wants to be friends.

So my question is, is this something I should just come to expect at this point in my life? should I not hope for anything serious and just expect casual, short lived, sporadic dating? It seems like those girls that want something serious are crazy and/or have a lot of baggage which makes them crave a relationship.

Can you summarize the given text in a few sentences?
<bot>: 3 Girls in a row now have given me the same reason for not wanting to continue. All really like me but want to focus on them and don't have time to seriously date. Is this something to expect through my 20s?