Sometimes it comes down to security/jealousy/control issues, even for mature age women in long term relationships.
If they see something is taking your time and your attention away from them, they try to split you from the car or whatever you are interested in. Several of my friends were pressured into selling their cars which had been around long before their girlfriend or wife had been on the scene. If you give in they will try it again on other things.
Mine got even more upset because 16 months ago I chose to restore another RS2000 without asking her permission first. To her it was like there was another woman in our relationship, even though she never saw the car and that the my time working on it never came out of our relationship time together. It was just "there" to her.