communication and trust and compromise are key. if they are someone who compromises for you, empathises with you, and communicates often, make sure you're giving that right back. so long as that back and forth is on the table, then just trust in them. holding secret worries about their actions only defies the trust you have in them and can create problems itself. and that goes both ways. and if they are actually someone who is taking advantage of the love you place in them, then that will inevitably come to show itself and you'll know.