sumac
Yes, it's quite an adjustment & it takes time to get it right. Apart from shopping & cooking, there are also the TIME issues of getting all the damn jobs done around the place when there are only 2 hands to do them! When you're working full-time this can really push you.
But be patient & things will come good! I promise!

For starters, you'll rediscover the foods that YOU really like (as opposed to those that best fitted the 2 of you) .... Right now here in this cold Oz winter, for me it's soup. I crave it & indulge myself with endless varieties: pumpkin the other day, followed by chicken & vegetable ... & last night it was lentils, spinach & tomatoes. I suspect pea & ham is next! I have no idea why I have this desire to to indulge in non-stop soup extravaganzas, but it feels good, is healthy & I'll continue till I get sick of it. My former partner hated all forms of soup with a vengeance. (Maybe this is part of the appeal?

) I guess what I'm saying is that it can be quite liberating to just suit yourself for a change.
I hope you get to enjoy it. I am.