1)Before Knowing Effect of Saturn in 7th house first we have to know about Saturan and 7th house. So you may read this
Lord Of Misfortune Shani—
Seventh House—Dara Bhav—-
2)7th house is belongs to Marrige and Lifepartner when Saturn occupy 7th house then native wife may be from lower class and don’t have fair Colour.Wife may be older than native or looking older from native.If Saturan is well placed then evil effect may reduced. A well placed Saturn indicating a steady and stable Marrige.Native may be in control of his Lifepartner.
3)If saturn is afflicted then its create problem in marrige life. If Sun is afflicted Saturan then there may be instability in marrige life.If Mars is afflicted Saturn then native may be suffering from legal problem in marrige life by his wife/husband or there may be quarrel/fighting between both.If Saturn is afflicted by Jupiter then marrige will be stable but may be mental stress between both.If Saturn is afflicted by Moon then there may be secret relationship of native/partner through which native marrige may be suffering.If Saturn is afflicted by mercury then life partner may suffering from unnecessary fears. If Saturn is afflicted by Rahu then there may be nature problem between both native. Overall Saturan is not bad in 7th house because Saturan gets Digbal in 7th House. Native wife may have old thoughts or belive in traditional policy.
4)If Saturn is afflicted in 7th House it may also cause for late marrige.Saturan involving with mars/Moon cause for illegal relation with lower caste women.It may also caused for more than one marrige or separation or divorce or in relation with widow women depanding on Horoscop.
5)7th House is Marak house and when Saturan placed in 7th House then native and wife may have ill health.If Saturn is heavily afflicted then it may cause for death of wife/husband. If may also cause for Native death.As Saturan in 7th aspects both 9th house(father) and 4th house (Mother) it may also cause health problem for both parents depanding on effect on those house.7th House Saturan cause for abdomen problem or ears problem.
6)7th House Saturan get impact on 9th house(Long travel house), 1st house(native birthplace) and 4th house(home) and 7th House(away from birthplace or wandering from birthplace) so this indicating Native may travel a lots or native may go to Forigen land or settled abord or native may house in Forigen land or native have in such profession where a lot of wandering from his home town.
7)7th House is Bhavat Bhavam for 10th house so Saturan in 10th house indicating Native may be industrialist(if saturan is Strong) other wise its indicating struggle is work and late success in work or may be in service of other.
8)7th House is belongs to Politics and saturan in 7th House indicating Native may success in Politics and if Saturan is Strong then may be got name and fame in Politics or may be good politicians.
9)7th House also belongs to Fame if Saturan is strongly placed then it may give Fame to native or weak or ill placed Saturan cause for Disfame.
10)Saturan in 7th House indicating Native may get help from Lower category people in there profession.
11)7th House is Bhavat Bhavam for 4th house so Saturan in 4th house indicating Native may have problem in getting happiness(Sukh) due to natural Melific effect of Saturan and also Saturan 10th aspects on 4th house. But if Saturan is well placed then its evil effect may reduced.
12)Saturan in 7th House aspects on 1st house so its impact on native physical constitutions so native may unfair colour or ugly looking or present himself in ugly way. It may be possibility native may be lazy from nature.