New verbs in English pretty much always take the 'regular' -ed past tense. Hence, as someone has said, as well as 'texted' we have 'Facebooked', 'e-mailed' (or now more probably 'emailed'), 'Hoovered' and of course 'phoned'. All those verbs start off as nouns. And when children are learning to speak they often form -ed past tenses of verbs that have 'irregular' pasts eg I goed, I sleeped.
'Text' would be a very unusual form in the past tense and is probably used because of analogy with 'irregular' past tenses such as 'went' and 'spent' which have different present tenses. There is though at least one precedent (and probably others but this is just the one I thought of); 'let' is the same in the present and past.
I hate, hate, hate 'text' as a past participle. I don't spend much time here in Pedants' corner, but I'm sure I started my own thread about it once. If I didn't, I should have done. In my view, 'texted' only sounds wrong because we've become so accustomed to being subjected to the appalling 'text'.