If two people have the same ascendant that can easily lead to the same routine, same arguments and same mood swings. My guess would be – same 7th house cusp can contribute to the boredom in a relationship.
I think there has to be the correct mix of commonness or compatability and growth or learning potential in 2 people’s charts. Too much similarity and it gets boring and too much Mars stuff and it gets to be angry bickering. Every relationship has a Karmic lesson, I always look at the Nodes and their House and Sign when looking at relationship charts. People can always get along for a few months but I want to look down the road a few years and see what Karmic stuff they’re working on and if they will grow together or if their individual needs will pull them in different directions, that is far more important than sun sign compatability.
I think anything Saturn-ized becomes “boring.” Saturn grounds and crystalizes, which is marriage itself. But to say “boring” means the crystallization of marriage in itself doesn’t provide pleasure. For an earth sign, for example, knowing and saying one is married is pleasure.
Personally, I don’t think it’s in the nature of anything that has Saturn applied to be interesting or fun. That’s why work is called “work” and marriage is not called “dating.”
Without seeing your chart, I would suggest to make the relationship come alive again you need to go to a deeper level. Get past Saturn and into Uranus (spontaneity), Neptune (imagination) and Pluto (revolution).
Some never get past Saturn or some find a new relationship to go back to the sun and through the inner planets again. You’ll always be back at Saturn eventually.