Not sure if this is about the marriage or the bike? I have been the "breadwinner" for the bulk of our 42 years together...that said, it is our money and our life together. We each have savings or investment accounts for big items we want to purchase as well as big items for our home and vehicles. We typically discuss any purchase over ~$300, and pay cash. Not a hassle and a good balance of power.
Bottom line, if I really wanted a new bike given I now have a nice road bike, and a good enough MTB and hybrid I barely ride, I'd save the cash for the new bike and probably sell the bike I'm replacing. It is just stuff...and amassing more stuff to gather dust won't improve our life together. Keep smiling.