Breaking up over text is cowardly. If the relationship meant anything, owe them the respect of doing it face-to-face (or at least on a call).

Be clear but kind. Don't drag it out or give false hope. "I care about you, but I'm not feeling a romantic connection anymore" is clear and respectful.

After the Breakup

Give them space. Don't immediately try to be friends. And definitely don't hook up the same night - that's just messy.