Mars-Saturn hard aspect can be non-life threatening as long as you have other good aspects to make up for it.
Your synastry looks pretty decent (Moon in sextile signs, Sun on Dsc/Jupiter, Sun opp Moon, planets in each others' 4/5 houses)... I believe there's affinity and romantic feelings. I haven't got the energy to scrutinise it in detail, sorry.
Honestly, your composite looks scattered and Chiron on Asc forms a t-square with 7H Uranus and 4H Saturn. This looks like the main challenge. Mars also in 7H conjunct Uranus square Saturn. Clash of the wills. You need to be very allowing with each other and address small issues as they come up, not letting them build into something irreparable. Sun square Jupiter can make you overly optimistic when together which caused you not to see the underlying issues that need to be addressed.