They're not ugly. They're made to match the house. It's just for the height of the doors they had to be pretty long. No switch backs, but they're both long L shapes. So it feels like it takes longer to walk down them compared to the stairs. It also kind of sucks if you want to go straight out into the yard and instead have to go sideways first. Also they just take up space by the doors that I would rather have available.
I agree with an earlier poster who said that, absent any agreement with your ex-girlfriend to the contrary, you can do whatever you want with
your house, including removing the ramp.
BUT, because the ramp and its installation cost a lot of money and your ex-girlfriend is expressing an interest in recovering some of her costs, contacting an attorney in your area first would be smart and giving your ex-girlfriend adequate notice before you dismantle the ramp also would be smart.
I remember purchasing a house years ago that had an open second floor balcony with a fitted removable wood flooring. At the closing, the elderly woman from whom we were purchasing the house insisted that the balcony’s wood flooring was not to be included in the sale. She wanted to back out of the sale over this so we said she could take the flooring. Of course, she had little use for the flooring in the assisted living facility where she was residing - and she never came to get it - but just offering her the flooring was enough to resolve the issue. I suspect if you offered the ramp to your ex-girlfriend if she wanted to come and get it, that would be enough to end the matter.