<human>: We have been dating over 3 years, would be 4 in June. I feel absolutely no spark anymore. We are both in school right now, 6 hours apart. Problem is he seems to be more in love with me than ever. 

Additionally, he's had a really rough year. In October of 2012 there was a death in his family that pretty greatly affected him. He also tends to go between being perfectly fine and happy, and getting extreme in ways like isolating himself from friends (I'm starting to wonder if he's bipolar, depressed, etc.). He said to me just now he'd get a psych eval if his insurance wasn't so bad. That is what *really* worries me. I feel like this and the distance and my lack of spark (which he knows about) are taking a toll on the relationship. He got really scared and started crying when I talked to him about me not feeling the spark anymore, fearing that I'd break up with him. I am honestly sort of contemplating it. I know that the good thing to do is to help your SO through their tough time, but I feel that it's taking a toll on us and I'm wondering if it will be worth it when the distance is over. (There's no end date, but it'll be at least another year.)

Give me a shortened version of the text
<bot>: I've lost spark, he hasn't. He also seems a tad mentally unstable, and the distance is really difficult. What do?