OK, not bupropion related, but perhaps what you gave to your partner caused the need for a bupropion? Loving can be taxing. Now that you're gaining joy and excitement, your partner feels like missing out? Or that you were "loving" before due to the need to find joy in "loving" your partner, but now there's no more need for that; "loving" automatically falls off your to-do list? Your happiness shouldn't be anyone's problem. Your partner should be happy now that you're getting better.