Thank you for writing. It sounds to me as if he wasn’t ready to increase the intimacy — and this was enough for him to back away. While this is devastating, it is also good that it happened now. If he had doubts, wasn’t talking to you about his concerns, and didn’t even have the guts to talk to you about it in person, then you are better off knowing this about him now. You don’t want to find out about his characer after you’re married.
Since he can’t give you any details about your behavior in this and only points to the normal stresses of life for the reasons he is breaking up, consider yourself lucky. You deserve to have someone who can talk about their concerns with you all along the way rather than escape the relationship.
During this transition time treat yourself well. Self-care is the most important thing as you recover from this loss. If he had this capacity to treat you this way at the end of the relationship (Skype? Really?) It is better, much better, for you not to be with him. You may also want some brief individual therapy as you move through this. Click the “Find Help” tab at the top of this page to locate someone in your area.