Hi my girl friend left me after our baby I was 21 she was 19 while being apart she was with other blokes I think she left me for sex is this a young person thing or what please help thanks

No, it may be a loose and wild moral person but just being young, they are often true and loyal and loving. How long were you all together ?
And if she left you to have sex with other people, better to find out now and be glad she is gone.

** of course I would assume there is a lot more to the story

How about some background into the relationship?

Maybe she wasn't ready to play house just yet and still had a few wild oats to sow... maybe she didn't want to feel like just a 'mom'... but instead wanted to be a young woman who was not tied to one particular person... maybe she has a void that she's trying to fill by making herself feel important when these multiple guys pick her for sex... maybe she's afraid of commitment...

Whatever her deal might be, I agree with Fr Chuck... better to find out now. Better to find out period...