Help!! Husband all of a sudden has trouble staying hard!!

Husband and I have been arguing a little more than the usual, Sunday was a bad one. Well Sunday night we had great sex! And Monday I got home from work and he was great, got hard just by seeing me, well when we tried to get the job done he couldn’t keep it! We let it go. Tuesday morning we where fine, Thursday morning as in today! Back at it again! Gets hard starting and then goes down!! Is it me? Is it someone else?? We have been together for 5 years this has never been an issue before!!! Please help!!!