A form of social discrimination based on the assumption that a conventional couple lifestyle is universally optimal and, therefore, desired. Internalized singaphobia is when someone does not accept themselves for being single.
While at the wedding, Dave was cajoled by his fellow groomsmen to get into position to "catch the guarder" with the other single men at the wedding. The groomsmen were singaphobic.
"Don't worry, Dave, you will eventually meet someone." This is a singaphobic statement if said to someone for whom you know nothing about their relationship aspirations.
The exists a social convention to buy newly married couples gifts to start their life together. Why don't people buy single people dishes and blenders? The absence of s similar convention is singaphobic.
Secretly, Sally hated herself for not being able to find a partner. This is internalized singaphobia.