sorry for making you confused. I am talking about the ruler of my 7th house in my natal chartI'm confused: are we talking natal or solar return chart? The ruler of your natal 7th house is Neptune or Jupiter depending what branch of astrolpgy you follow (traditional or modern), that's correct but you've attached a natal-solar return comparison. The ruler of your SR 7th house appears to be Saturn (the Asc is in Cancer?)
The ruler of your 7th House is Jupitersorry for making you confused.
I am talking about the ruler of my 7th house in my natal chart
The ruler of your 7th House is Jupiter
whether using modern or traditional astrology
simply because
even modern astrologers only assign Neptune as CO-RULER
Pisces is on the 7th house cusp. Its traditional ruler is Jupiter. Its modern ruler is Neptune. Some astrologers choose one or the other. I use both.
Jupiter ruling the 7th house and in fall in Capricorn is likely to cause problems even getting into relationships and a high potential for instability and loss of them.
It is exchanged with the 5th lord Saturn. This also will tend to indicate some instability when it comes to partners (and in fact, is an exchange that can give more than one significant partner in life). Normally this occurs because the person is "lucky" with the opposite sex and their relationship becomes strained due to the constant attention and "temptation" they may get.
However, since the Jupiter is in Capricorn it likely won't manifest that way at all...
First get a good grasp of the meanings of the houses. For example, the 5th rules one's children, but also your recreational or leisure activities. When your sun is in a particular house, usually at least one of its meanings is very important to you.
Then consider: "The house over which a planet rules serves the purposes of the house in which that planet stands."
How do you determine the "house over which a planet rules...."?
I'm not sure about it though, but if you are looking at your birth chart in a specific house:
example in my seventh house, Pisces is there. They said Pisces is ruled by Jupiter and co-rules by Neptune.
For example in your eight house, Virgo is there. Virgo is ruled by Mercury. So, your eight house ruler is Mercury. I guess?