A quick explanation on dialectics.
dialectic before it became associated with idealism and then materialism stood on its own, theorized in ancient greece.
In Aristotlean dialectic is where you find the thesis-antithesis-synthesis structure. It doesn't really apply to diamat but I digress (there are better words to explain diamats structure and it has its own laws as well)
thesis-antithesis-synthesis is often misunderstood as "I agree, you disagree, the synthesis is you agreeing with me". to be clear here I'm talking about the rudimentary dialectic, not diamat.
in aristotle's dialectic the synthesis is the third new thing, something new emerges which did not exist before. Therefore it cannot be the thesis because the thesis existed prior to the 'debate'. it cannot be the antithesis for the same reason.
Take an example I've just gone through. My thesis might be, the way this particular group does agitprop for their party on twitter sucks - it's too corporate and says nothing of substance. the antithesis might be, I think it actually works and we should emulate their style.
The synthesis may be: we won't adopt this other group's style but we have identified deficiencies in how we post about our activism and we will improve on those particular aspects, we both agree on this.
Which is a position neither of you started with; if you work backwards from the synthesis up to the thesis and antithesis you will see it if it doesn't make a lot of sense yet.