Why?  His Mars is trine mine by sign but not by degree -- 21 vs 12 degrees. 

I just learned about degrees and orbs recently. In all but one of my long-term relationships the man's Mars aspected my Venus by sign, maybe not by degrees.. will have to go back to astro and check. I'm old school. I need for a man to chase me. If my Venus doesn't get his Mars all hot and bothered I really don't see how there can be a chase. 

Okay. The most recent ex, the man I had the most serious synastry with, has Mars in Sagittarius at six degrees. My Venus is in Aquarius at sixteen degrees.  So we have the sextile but it's wide. I'd love a much tighter aspect. That's just me. I place a high premium on Mars-Venus. Him Tarzan. Me Jane.

My ex to whom I was engaged had Mars trine my Mars and no Venus Mars contact at all.  He did all the chasing.  Plus our synastry wasn't as good as the one I posted above.   Let's not forget that timing can often override synastry. You can meet the right man at the wrong time. 

Yes. Many factors to consider.

Just checked out my ex-husband's (my second husband) chart at astro. We have mutual Mars-Venus trine to the degree. Lots of other favorable stuff. We are still friends. I'm very lucky because we are raising our son together. No acrimony whatsoever.