Insecurities...

I can't help but feel like I need to lose weight for my boyfriend, my boyfriend is so active and fit as he is a footballer and I don't feel like I'm his type at all, I feel as though throughout the relationship I've just put on more weight, but I actually love just going out and doing active things such as swimming and hikes, he keeps bringing up the fact that he wants us both to join a gym and workout together but I just don't feel comfortable enough like I'm an embarrassment to him... I try to blame the contraceptive implant I have and just say that it's water weight but I can only use that for so long...