You are mixing 2 schools of astrology and getting confused. Darakarka represents Spouse as per Jaimini astrology, whereas Mars rules your 7th house as per parashari astrology. As I follow parashari astrology for me I will base my predictions upon the 7th lord and its placement which is Mars. I will also consider looking at Jupiter which is the karka for husband and Venus which is the karka for wife and also marriage.
7th house which is the house of marriage and marital happiness is ruled by Mars. Rahu aspects the 7th house and also 7th lord Mars. 7th lord Mars in the house of gains, is not good either. The horoscope is weak on the marital front. The possibility of marriage is there is your horoscope after lot of delays and obstacles. The chances of marriage are after the 31st year of birth.