Appetite and anger, from one source
Mars is drive, appetite and anger, and astrologers treat these as one force pointed in different directions. A person who pursues a crush head-on will probably also tell you straight away when they’re annoyed. Someone who approaches desire slowly often gets angry slowly, and you may not hear about it until next Thursday.
It takes about two years to go round the zodiac, so it stays in a sign for around six or seven weeks on average. That makes it personal without being as fleeting as the Moon.
What it does in a comparison
In a report, Mars ties to the Passion area. When your Mars meets their Venus there’s usually pull, as in Venus square Mars. Against their Sun, as in Sun square Mars, there can be rivalry that gets a lot done or wears you both out. Against their Saturn, one person’s go runs into the other’s wait, and Saturn square Mars is the classic frustrating version.
Mars contacts add energy, and what that energy does depends on the two of you. Plenty of couples with heat between them use it to train for races and renovate houses.
Fighting fair
Compare how you each behave once you’re angry. One may want it settled tonight while the other needs a walk first. Agreeing on this ahead of time is worth a lot, since a walk stops looking like abandonment when you’ve both agreed to it.
A word of care: a chart can describe a hot temper as a style. It doesn’t excuse anyone frightening or hurting you, and no Mars placement should talk you into putting up with it.