To see how two people relate to each other, you need to see where one's planets fall on the other's birth chart, which is called synastry.



There's a good reference site on that I can recommend you:

http://www.astrology-numerology.com/synastryaspects.html

http://www.astrology-numerology.com/synastry-houses.html



Your natal Jupiter in the 7th squares (90 degree) your Sagittarian planets in the 4th. So you yourself have some internal conflicts between partnership and home life. It's probably not entirely her fault that your relationship blows hot and cold. I think having so many Sagittarian planets in the 4th house is itself ironic and contradictory. Sagittarius likes to be free, and here it has a serious attachment to a base - family and home. That's the difference you need to resolve yourself, because you are still predominantly a freedom-loving (fire/mutable) person.