Yep, definitely a good time to take plan B. Also, the responsibility to use protection is on both partners. Being as he was sober he was in a better position to manage this and made an active choice not to. You bear the burden of what happens and dealing with it, but he gets to have fun and run away. Very uncool.
I would consider how well you could really consent and if you want people who don't care about that to be involved in your life. You, along with everyone else, deserve someone who will not take advantage of the situation to get off at your expense. Also, he should really foot at least half the bill for the plan B, without him it would not be needed and if it becomes a larger and more expensive problem it would be something he was responsible for there too. Any self respecting person should pay for their share.
The battery degradation is overblown with lithium iron phosphate batteries, which is what is in the Bluetti Elite 30. If you aren't putting it through deep discharge (greater than 80%) or high temperatures (above 30°C) it should still work well for a long time. The higher your draw on it, pushing up to that 600W limit, the worse the impact is too.
That said, it can work very well as a UPS for a freezer like what I have mine for, and adding a solar panel extends the usefulness of it a lot. I have a 200W panel which gives around 130-170W at any given time through the day, leading to a full charge in theory in about 2 hours. My freezer pulls around 60-80W with transient spikes to 700W when starting the compressor, but the power station can boost to cover that need for a short time. Over a day I use about 550Wh per day, so about 4 hours of sun per day in theory. It should be covered by the panel I have but the capacity is a little low so I can't get through the night at this point, it has to switch over to AC after a while. Still, during the hottest hours where I need the most power I am getting solar to do it, so that's handy.
Anyway, yes, they are useful, another more powerful system is definitely in the cards for me, but they are a great first step and handy as a backup for bad weather.