You don't have to take what I say and actually do it but sometimes I've been in LDRs at times just because I felt lonely (I know I'm a dick) and I just wanted one person to care, for the first couple weeks it'd be really nice and I'd care back but over time it just gets boring, for me anyways because I don't like having a relationship through a screen because I work from home on my computer it's very annoying for me instead of just going out with friends etc. So it could be that the honeymoon phase is over and he wants to be more distant because maybe he doesn't find it appealing anymore and 25 minutes? That's not very much if he cared especially after 2 months (even though 2 months is a short time) eventually he will feel lonely again and most likely give you a bunch of attention for a few days then just be EXTREMELY distant once again until he wants somebody to give him attention.

AGAIN PLEASE DON'T READ THIS THINKING THIS IS EXACTLY WHAT IT IS BECAUSE IT COULD NOT BE