Well, try and be yourself! Everyone has their own unique style, you just have to find it. For fair skin bright colors or prints will work perfectly for you. Are you sure it's the way you dress he's losing interest in? Like when my boyfriend and I went trough a rough patch he told me I wasn't as affectionate as I used to be and just not as lovey towards him. I hadn't even noticed! I just got used to us together and it became a routine. So see if there is anything like that :)
Here are some sites that I like to shop at, floral prints and bright colors are a hit this year :)
*Macy's (the clearance section in juniors has proven really well here! I don't spend more than 20.00 on a top. Sometimes I'll splurge and get something more on the pricey side if I feel it can be mixed and matched.)
*H&M (They sadly don't have an online store :( so it depends where you live.)
*Target (Some of their summer dresses are darling!)
Here is the splurge site haha, I RARELY get anything from here. The only time I do is if I need a dress for an important event. link
the clothing is expensive by most of the jewelry is pretty well priced!