Everybody has tough decisions to make and I believe God understands the ones we choose if they feel right in our heart. Your fiance shouldn't beat himself up over it but if his heart tells him his actions are correct, the best thing you can do is support him and not feel bad.
I used my tithe money to help my fiancé with rent. We fast in August on Fridays but he is fasting for the entire month for me as result of my actions. I can't help but feel bad. Should I feel this way?
Is that some sort of redundant symbolism? .. Not even logical. How does someone doing themself harm in a form of self sacrifice provide any benefit to someone else's behaviour or actions. You don't ask forgiveness or commit some crazy sacrifice in an effort of reconcilliation or forgiveness for someone else .. He is wasting his time, not to mention, health. Just his mere disrespect and disregard for his own health for 'the cause' should sound an alarm .. Loud and clear.