Most Helpful Guy
Honestly, relationships rarely work if the partner is always hanging with the opposite sex due to temptations and or opportunities... I'm not sure if your uber religious and are waiting for marriage for sex, but if you are not and are trying to at least save it for the right person... I'd go for someone who hangs mostly with their own sex.
For example. Bill liked Mary and Mary liked Bill. Mary didn't like to hang out with girls because she claimed there was to much drama so Mary had guy friends she would hang out with. One day Bill and Mary had a silly little argument and decided to get a way from each other to cool down and discuss it later more claim. Mary decided she would go see her friends... Mary still upset about the argument, starts to vent to one of her guy friends named Bob. Bob takes advantage of her distress and starts downing Bill. Mary has a few drinks with Bob and next thing she knows they are making out and before she knows it, she wakes up naked beside Bob in his bed. Now she feels horrible and her relationship is ruined.
Moral of the story: Don't put yourself in situations that can lead to potential disasters
You can change the story around to read it the other way around. Bill is Mary and Mary is Bill and Bob is Heather... to be fair to both sexes.
This does happen and it happens very often. Some never speak of it and others guilt is so bad they purposely ruin the relationship to release the guilt.