I don’t know what to do

My fiancé did year long a post doc. He asked me to go with him on the condition I get my license. He proposed one weekend September 2019 and left the following Monday. I planned to go asap but getting my license took until March. The world shutdown right after I got my license. I didn’t move(I brought up moving when things started opening back up but he refused) but I went down in August to help him move back. We get back, live with his mom for a year or so then move out of the state for his new job.

We’ve started planning our big wedding and today he revealed that he’s feeling resentment over me not going down there, and it’s not my fault and that since he’s come back it feels different and he’s hoping it’ll change. He admitted he gets angry when he thinks about what happened during his post doc(ie. Me not being there, the pandemic, him being isolated ect.) and takes it out on me(he’ll just get mad over stupid stuff, never yelling or violent just visibly upset and short). He also brought up how he shouldn’t have proposed then left.

I don’t know what to do. I’m going to suggest we do therapy to solve this.