Count me in as someone who understands.
I was the HOT girlfriend/wife back in the day. My husband LOVED that his friends were jealous. He never SAID it out loud, but you could tell. Now, it is four kids and a good 100+ pounds later and I know things are "different". However, I truely believe what was said by others here, A LOT of it, has to do with my perception of me. When I was my thinner self, I would flirt with my husband, I would dress different, I would initiate..well, I'd INITIATE. I was more comfortable with my body so things were different. Now, I just want to keep as many clothes on as possible and hurry up before one of the babies wakes up and hurry up!...I'm tired and want to go to sleep!
That doesn't make my husband feel desired.
Luckily, my husband isn't into porn. I'm not a fool, he's a guy but my husband would much rather do it then LOOK at it. However, I see him checking out a some chics on tv with nice bodies. I see it, he knows I see it (mainly because I let him KNOW I see it). I know who he thinks is hot. I don't like it, but that is my insecurity.
That's what a lot of it is. Insecurity. My BIL had a girlfriend for 4 years that was a big girl. She was probably close to 300 pounds BUT, Betsy had ATTITUDE. She flirted, she was outgoing, she was lively, she dressed nice...she was so comfortable in her skin. THAT was a turn on. Her size was never an issue.
Guys are easy. A stiff breeze will turn them on. They don't think about sex like we do. Sometimes I think we over think it. We feel bad about ourselves so how could they not?! They are the ones looking at us! Right? I know. I've thought all the same thoughts. What turns a guy on the most? A woman that WANTS to do it and isn't too inhibited. I really believe that. Do I practise what I preach? Nah. I am working on it though.
Of course, blood pressure medicine really CAN effect things in that department. That is legit.
I just wanted to chime in too so you would know you are NOT alone in the way you feel. Not by a longshot.
Loose weight for you...not for him. As your confidence in YOU grows, I bet you find some of these issue start to fade. I am no expert but that is my opinion.