My mother told me a long time ago that in evaluating a potential boyfriend, watch how he treats you when it's just the two of you alone versus when you're in a group with other people.
If they treat you very differently in the different environments, IMHO it's an indirect manifestation of a serious underlying problem. There is no reason for the disparity. If they truly like you, they'll treat you well regardless of the company.
Obviously, there will be differences in peoples' behaviour in public versus in the back seat for example, but generally speaking, it should be consistent.
Two very close friends of mine have been in such relationships now. Both situations ended poorly.
To everyone I care about who is still looking for love:
Please find someone who treats you like the worthwhile person that you are and with the respect you deserve, in any and every context.