Apparently I have a severe latex allergy. So what condoms can I use if gay?

Natural ones. There are natural, and other condoms clearly labeled "do not contain latex". Just look carefully on the box.
Polyurathane. Individuals with a latex allergy can use polyurethane condoms for sexual activity, regardless of sexual orientation.
Polyurethane. Polyurethane condoms are safe for latex allergic individuals and are an effective barrier against std's including hiv.