I have done dumb things. Across the spectrum of stupidity. Things I had a lot of regret over later. It's an interesting question whether the grief does that or the loneliness. As someone once wrote (I wish I could properly attribute - but grief brain allows me to remember some things and not others), "loneliness will break you".
A lot of the stupidity has to do with not being able to make a decision. It's so easy to be in a state of paralysis where everything seems too much and you flip unopened bills on the desk and forget to deal with them until it becomes a crisis. In the past, I was efficient and dealt with things productively - that was a measure of worth and competence. In the last two years I have left more stuff undone because I just didn't have the will to address them. Lately I have had more energy around small things - like checking insurance rates, and cell phone plans, and telephone line charges, and finding all kinds of opportunities for cost savings. I think how stupid I've been to let this stuff go - what a waste of resources. Yet, I need to be gentle on myself, and think about why it's good now to address it, and what it means for the future, and not beat myself up for past stupidity.
Then there are the stupid decisions, ones taken in haste. I tried to separate out the irrevocable ones from the "no harm, no foul" ones. But in the fog of grief my analytical powers are diminished, and the criteria by which I would usually make a decision strangely absent, and new criteria (untested and unvalidated) show up. Such as, "does this get me out of my pain of loneliness", rather than a more thoughtful, "does this impact my children negatively?".
I'll address new relationships in different set of posts - it opens up a whole new realm of potential stupidity.