Well, Inviting another guy to her house is totally not right. If i did that with a girl my fiance would flip on me and If she did it to me the same would be expected because the feelings are mutual no matter the amount of the trust, that is not something you do. The only true way to keep a relationship usually is when your friends are all of the same sex and nothing more, only exceptions are usually lesbians or gay males which even then could bring about a issue with some couples. In reality it is rather hard to deal with it especially when you have been screwed over before it is hard to trust again, therefore you must find the common ground. Otherwise the relationship will not last or work, wearing another guys jacket is totally fucked up and that would piss me off to high hell cause i am protective of my girl, inviting her over would get the persons teeth broken. Sometimes that is exactly what the girl wants, she wants to see how seriously in love you are with her and will you go out of length to ensure she stays yours.