Is it normal to be 2 weeks late or even a missed period due to stress?48 days sense last period, have not had sex in a year, what could be the reason ?

Stress amenorrhea: It is very common for stress to make menstrual periods irregular. For example, college students may miss a period or have a late period after finals week because of the stress.

Yes could be stress: But that is a diagnosis of exclusion meaning everything else needs to be ruled out so u need an exam , blood work and a pelvic ultrasound by a gyn.