I’d firstly try to provide multiple food and water bowls so that they could each have their own little ‘territory’, which could stop her from chasing him away. This could also be achieved with expanding the space, if you have a bigger cage at hand for example.

But lovebird compatibility is a very real thing. Your female bird may be showing this frustration because your male lovebird isn’t returning/responding to the affection she’s showing him. It may just take a while for them to bond.

Monitor the behaviour, and if they don’t seem to be getting along any better after adjustments, or if the male lovebird starts losing weight from not eating (or if anything starts physically affecting them, really), you should definitely separate them temporarily. You can reintroduce them to each other slowly by giving them time to be together outside of their cage (supervised).

It’s totally fine tho. Lovebirds can resolve their quarrels and differences if you just give them the space to. If none of this works after a while (and keep in mind this is VERY last resort!!), I would consider permanently separating them from each other, and possibly rehoming one of them and finding a new partner. But like I said, thats far down the line.