Hi peeps, I wanted to share what I'm currently reading, because it's one of the best books around regarding synastries and other "love aspects" in one's own chart. The author is Stephen Arroyo and the Book is "Relationships and life cycles"
About having Saturn in 7th house, natal chart: the placement of Saturn doesn't indicate a "single life", or anything doomed in the relationships matters, it could have been true in the past, where the age to get married was around 20, and we know with Saturn in there, the person wants to be sure of their decision, and that takes time. It's not a position for "marriage at first sight". But since nowadays it's even uncommon for most people to get married before 30, or to get married at all, Saturn in 7th shouldn't be considered as a factor for a delayed marriage.
The thing with Saturn is that, wherever it is, it will give a lot of importance to that field, quite the contrary of what tradition says. Basically, you give so much importance to the relationships with someone else, when your Saturn in in 7th, that you want to be sure that that's the right person and you're doing the correct thing, with no rush.
Hope it helped a bit~