Struggling to have casual conversations about what I perceive as serious topics with my partner

Hi! I am really struggling with this issue and really need some advice on how to change my behavior. As the title says I am really struggling to have certain conversations with my partner without taking them overly seriously or getting upset in tone and manner. We both have diagnosed ADHD.

This has been going on for a while now but recently my partner told me they feel like they can’t talk to me about anything without me taking the conversation too seriously or me getting upset or me taking up too much space. That really hurt me—not because I’m offended or don’t think it’s an issue, because it definitely is an issue, but because I can see that I am hurting them with this behavior and I want to change. The last thing I want to do is hurt him or make him feel like he can’t express anything to me.

The particular context in which this came up was an instance where my partner was excitedly talking about changing what our 5 year plan was. We have been together for over 3 years now and have been talking about wanting to move for going on a year. We were out and about and he started talking about the possibility of wanting to stay where we were instead of moving. I found this fairly distressing as I said to me, we had been talking seriously about moving and so I took this suggestion as serious when he was merely thinking out loud. I did get upset and said I was confused as this was kind of coming out of nowhere and that I’d like to talk more about it when we got home and I could really put some thought into it. His response was that he was just thinking out loud and wasn’t fully serious about wanting to stay, just tossing ideas around. I said I took it seriously because he has been so serious about wanting to move. He said that the conversations we had about moving were never that serious to him while I maintained I thought we had been seriously talking about moving.

I think this is maybe stemming from my own black and white thinking? I tend to take things very seriously and at what my brain interprets to be face value. I want to be able to casually talk about these sorts of things, especially because that important to him and part of how he thinks and processes his emotions. I understand that not every conversation about our future or other topics needs to be serious but that tends to be my default mode. I’m also very defensive and trying very hard to break down that pattern as well.

Any and all advice, tips, or tricks are appreciated. I want my partner to feel like he can bounce ideas off of me or talk to me about anything and be able to trust that I’m not going to go into ultra serious mode and get upset. Thank you :(