Conjunctions and stelliums of the composite Sun or Moon show up very frequently in long lasting relationships. Especially if they are also sextile or trine to other planets as this strengthens them. In both synastry and composites the strength of the luminaries are strong indicators of important relationships. Another feature of very lasting marriages that I have seen is the Composite Nodes squaring the stellium of the Moon or Sun or on the Sun or Moon This chart has this feature also.
The Moon is in H6, usually a very difficult placement for romantic relationships, but with the Sun in H10 this might be an excellent chart for working together.The Mars trine Saturn is also a great aspect for working together.
The intensity of this Moon/Pluto indicate powerful emotions and a desire for deep connection, deep psychological purging and exploration and in Scorpio this conjunction is even that much stronger adding to the intensity. These Moon/Pluto combinations can manifest as compulsive and obsessive behaviors, and H6 is a house that is about self-improvement, and critical analysis. I would caution against becoming excessively critical of each other or trying to change each other .This could be tricky to manage, but the rest of the chart is good.
I would like to se the synastry however as I never like to make judgements on the composite alone.