Only a fool trusts somebody 100%
Why is having hot filthy sex with a girl "using her". MAYBE she wanted it just as much?

Even if the girls "lad mates" did use her for sex, why should you care? She's old enough to make up her own mind. You have to get over this mentality of feeling threatened by exs and her high sex drive and high sexual desire for cock. It will only get in your way in your pursuit for happiness.

Like someone else said, I WANT GIRLS who like threesomes. Think of the possibilities