Writing websites in HTML (and not XHTML) does not mean you don't follow web standards. Anyone claiming otherwise simply lies. Just forget all bad things about HTML that Jeffrey Zeldman writes in his Designing With Web Standards book. He lies, too.
There is simply no reason to use XHTML over HTML. What's more you should even beware of XHTML, especially when you're sending your websites as text/html (it's harmful) and you always do for old handicapped uncle Internet Explorer.
So don't be stubborn. There's no shame in confessing to giving in XHTML propaganda. The most important is to realize that web standards are not about adding (with great reverence and pride) XHTML doctype and bunch of self-closing tags. It does not make your site any better. As a matter of fact, it is Strict word that REALLY matter and not XHTML. Focus on that.