It probably isn’t you. Health changes can sometimes come on fast with some conditions and that can lead to these issues. Trust me, if he wasn’t interested in you he would not have married you.

It could just because of aging. Or his ex-wife was just much hotter than you. You choose.

yes probably he does not find you enough sexy but as he live with you he finds your caracter More interesting

he's getting older. having erection problems is a normal thing as men age

How do you know! And usually it's a physical problem men have. Stop taking it personally. I'm sure that doesn't help.

Maybe talk with him. Its deffinantly possible that there's some psychological/physical need that's not being met and his dick is letting you know. Psychologicaly is a significant part of intimacy and sex.