Can you get him or you off of the joint phone plan?
I just switched over to this company called Kitty Wireless, it's really cheap if money is an issue.
But you care because you are a person whose emotions run deep, instead of focusing on surface distractions. Think about it: these connections aren't authentic. They don't involve true intimacy. He's using these women. It's a truly disgusting way to be.
I know that it still hurts that he is choosing and preferring such a despicable pursuit, that his ego and desire to feel wanted and get the validating thrill of conquest take priority over a good, loving relationship. But that is his brokenness. It's sad and demoralizing to see it--it makes your giving so much of yourself to him in the past seem like a farce, since he clearly can't appreciate the worth of what you offered, and it is a slap in the face to think something you know is precious is being thrown away (those doubts of 'what if he's getting something better?' that creep in), but really and truly it is far better to be alone than to be the type of person with so little ability to act with integrity.
The fact is, you are a good and loving person who is realizing that your love was going to someone who never deserved it. It's a harsh awakening. Don't beat yourself up for your feelings even though there isn't a strong rational basis for them, and remember--you are the one who can hold your head high, and that is going to count for a lot in your future happiness versus his future continued dissatisfaction.