Yes, your payment history will reflect on his reports being an AU. Call and have your fiance removed. Seems with 3 years of credit building themselves, timely payment, low utilization, the scores should improve.
In underwriting, they may request any AUs to be removed to gauge their personal credit worthiness. An AU for scoring purposes should only be if the person they are using is using a card with a good bit longer credit history than their own. Example card was open 5 years or more, and they only had a month to a year history. It must be either 0 or low utilization, as they will be using their cards also for payment history. Try having your finance paid all cards to zero except one, preferably a bank card with a balance greater than 0 but no higher than 8.9%% of total tradeline. Sometimes you can be dinged for carrying a balance, regardless of low amount, on over 2. 3 cards or more.
