Feeling unattractive

Ok so iv been with my boyfriend comming up to 2 years he was my first sexual partner first relationship everything at the beginning he was all over me we had sex a lot but lately the past 7 or 8 months we hardly ever have sex it's like he's completely gone off me I tell him I need sex n talk to him about the lack of sex but he just seems to brush it off as him being tired or stressed and even when we do have sex there's no foreplay for me I initiate sex I go down on him I don't get touched at all until actual penetration and even when we do have sex feel like he's just not into it and only doing it because iv guilt tripped him into it I just don't know how to make myself more desireable to him anyone else experienced this or know any tips I can use would really appreciate the help thanks