You don’t really want to talk to them on the phone
No one talks much on the phone any way. But when it comes to relationships, especially new ones, you want to talk to them, and the frequency might reduce as the relationship goes on, but the anticipation should remain ever the same. If this changes, it’s pretty obvious that you don’t really want to talk to them.
They aren’t the first ones to hear any good news you get
The relationship you have with them isn’t like any other relationship. You should want to share everything with them, and at the very moment that it happens. If they’re not the first ones to pop into your head when you have good news to share, it’s a definite sign.

You’re arguing over petty things
Arguments find their way in every relationship. You just can’t avoid them. Depending on how you deal with them could either damage or strengthen your relationship. However if you fight over something as insignificant as making the coffee too strong, it’s time you think about what’s actually causing this annoyance. It definitely has to be something much more than that, something about the relationship that isn’t right.