she led me on for 5 months (i still love her)

we met on my birthday last year. we met and we were eachothers first kiss. the problem with me is that it was my first relationship so i didnt know how to treat her but she didnt mind. she really loved my company. it was perfect. fast forward to the start of this year, she slowly became drier but still said she loved me. iw as trying ti change for her and i let it slide until 3 weeks ago. she told me she had a boyfriend since early march and it broke my heart because she was my first everything. my first kiss. even while she had a boyfriend. she sent me a bikini picture and said she missed me when i didnt respond, she said she loved me and i said i love you more. i cant believe she would do this and i have trouble eating it really hurts. i dont know what to do.