Shit man, I'm sorry. Besides the sleeping in the bed part, you really ought to stick to that course of action if you ever find yourself in a situation like that again, no one who wants an open relationship is worth being with, regardless of whether they'll accept not having one.
By the way, in regards to marriage material, I'm young, and I therefore don't have any far reaching life experience, but from everything I've seen and done, I'll tell you this much, unless you're in an isolated society with a virgin Christian culture (by this I don't mean a cult or a church, I mean an area), the virgin Christian girls are probably quite emotionally damaged, they're not all degenerate, but odds are they have issues, plenty of which you can't detect. I'm sure some people will disagree with what I'll tell you, but you're 18, we may have different pasts, but ultimately I left everything behind me, so besides different mental garbage, we could get the same end result. Become a person you can respect, this is absolutely essential, if you're in the state you sound like you're in, you're toxic, forget every girl you know, anyone who has known you before won't have a good mental image of you, you need a girl to really look up to you. Once you think you've gotten yourself in a decent physical and mental shape, take a hard look at your mind, you're supposed to be able to stand up for yourself and the things you care about, but it's absolutely important you've put out all your demons, otherwise you might find yourself lashing out. When you're finally in a proper state, you should probably leave wherever you currently are, I recommend going to the city, if you are in the city then go deeper, find work, something that has you around people, do your job perfectly, always put in extra hours, never bitch about anything, keep a very workoriented relationship with your coworkers, don't initiate conversations that aren't about your job, your workplace is the one place you should always be stoic. If you go through all this shit, if you're determined and work hard you can get yourself here in a year, when you get to the point when everyone greatly respects you at your workplace, even though they consider you withdrawn, you're ready to start looking for new friends and pursuing any women that might interest you. Ultimately with women, there are two rules you have to follow. 1. You have to actually like her, she has to be attractive, don't settle on a fat chick who annoys you because there's a hole attached to her. 2. She has to look up to you, not just friends, not just think you're hot, certainly not a fucking pityfuck, if she doesn't look up to you its not going to work. Oh and before you think you can make someone look up to you, we all fucking know people form semipermanent opinions on each other after the first time they notice eachother, if she isn't looking up to you after that, it probably won't work, unless you're seperated for a lengthy duration inbetween.
Lastly, I don't recommend virgin Christian girls, not from personal experience, but from everything I've seen in life in regards to those types, they're usually as emotionally damaged as tumblr whales, it just doesn't show as easily, the second they feel confident enought to do so, they'll be riding the cock carousel, while still relying on you for moral support, they won't be upfront about wanting an open relationship, and they'll rely on pity, potentially threaten selfharm, to get you to remain their moral support. Not everyone of them are like this, obviously, but this type of person is likely highly alienated, have you ever read Brave New World? The beta male main character is the embodiment of most of these women, they'll act the way he acted when he got confidence. I recommend a happy, talkative 10/10 fifteen, sixteen or seventeen year old girl, whose lived a happy life, at the center of attention, has a good relationship with her parents, and has had a couple boyfriends before at best. She won't be a virgin, but she won't turn into a whore. Again though, if virgin Christian girl is the only thing you like, you have to go with that, you have to like the person you're with, odds are to find a good one you'd have to go to a place outside degenerate culture, then you'd have to stay in that place forever, shit culture seeps into most everyone that dive into it, especially women.