Can I Trust him again?

I have been with my partner for nearly 3 years and thought we were really happy together. After a holiday away we agreed to find a place together.

I was over the moon. Then on the way to work during testing my partner, i got a random text from him which read, "morning baby send me more please xx".

This has opened up one hell of a can of worms and after 2 days of denial and tears he told me he had met a woman on the internet given her his number and had been speaking with her for over a month!

My whole world has been turned upside down and whilst i still love my partner so much i dont know if im right to carry the relationship on and let him make it up to me or end it now and save myself a lifetime of heartache!

I want it to work so much but even now he's not telling me the full story! He wont tell me anything about this woman . . . who she is, where shes from - nothing!

its driving me crazy!

Please help!

Axx