I hope you correct my text

You were the definitely only love
I am not able to start another love with someone
I don't want,,,,,
听起来自然吗？

It is a little difficult to correct without context but;
'You were definitely the only love'
I am unsure whether past tense was intended, but if not, then substitute 'were' with 'are'.
'I am unable to start another love with someone else'
'Not able' can be used but unable seems more natural.
'I don't want that'
In a standard sentence/clause, it consists of a subject, verb, object. In this case 'I' is the subject, 'don't want' is the verb, but you're missing the object. I put in 'that' as an example, but as I don't know the context, I can't that 'that' would be the correct word to use.