I imagine this was a difficult question to put forward, but I very much appreciate you doing so. My reaction and advice have more to do with the raw dynamics of the condition, rather than an emotional response, as you are having. That being said, the relationship doesn’t sound like it has much value, appeal, or future. I believe this is the case for several reasons.
First, you have not been together long enough to have enough experience with each other on which to base a lifetime decision to marry. Three months, even if it were all at once, would be only the thinnest slice of time to base such a huge decision on. The fact that you are not available to each other, and you are separated by half the globe, doesn’t make for a good beginning. Particularly when you are not happy with his phone calls. His negativity is a known turnoff, and you are feeling like you are at risk for endlessly taking care of him. All of these are issues you would want to sort through before you are married, not after.
He has not been able to sustain his independence, and his negativity has you in line to become his cheerleader. Not a role you want to assume.
Don’t push the river. Keep it simple. You have visited him twice, and, let me guess, “circumstances” have prevented him from coming here to visit you. Already you have invested more in the relationship than he has. Why the rush to get married? Research demonstrates that marital satisfaction decreases over time, so you need to start on the highest ground possible. If you have these many doubts and concerns and frustrating feelings I would honor them and give yourself more time to assess whether or not the two of you belong together. It sounds to me like he has a good deal of growing up to do to be ready for a mutual commitment and reciprocal relationship.
Normally I would recommend couples counseling, but in this case I am going to recommend virtual couples counseling. Perhaps you can find a therapist willing to consult with the two of you via Skype or on a conference call. This would be difficult, but in the age of travel and technology it may be an option. Perhaps one of our online counselors could help.
Wishing you patience and peace,