We got together when we were 20 but soon turned to long distance relationship. I was a small guy to begin and she was bigger than me but we never minded then. Four years passed and she gained 20 kgs to become around 85kgs with 152cms and I gained 10 to around 66kg with 173cms. She also became quite sick in this time with diabetes and arthritis which made it harder for her to exercise and lose weight. I still do love her and don't wanna make her feel conscious about her weight. But it's just that I don't feel attracted towards her anymore. We do have sex when we meet and sometimes I feel a bit suffocated but we do love each other and make each other feel good. I love her company and she understands me very well. But in my heart I also feel the urge to be with someone fitter and sexier and that makes me guilty for even about thinking about leaving her in bad times. I think I'll probably just decide to keep her happier this way. AITA here?