Struggled and failed

I've failed. I went so long before last yr not cutting yet now it is my go to. I don't even know y I did it the other day. I've been very down for weeks and I thought I was just blah but ok. I cannot tell my wife she'd be very upset disappointed and stressed by it. She worries so much when I'm down like this and I try so hard not to be and I try to hide it but I guess I'm awful at it. For the first time in my life I feel so much shame for giving in.

Now I look at the fresh cuts and just hate myself even more. I've no idea what to do. I know it's bad but when is it too much and I have to get help or message T? I see T every Monday now and I'll probably speak of it since she's pretty perceptive of when I'm hiding something. Only problem is the last time I told her she blocked the door and almost don't let me leave. This only makes it worse. It makes me feel trapped. It makes me very paranoid and anxious irritable and very possibly dangerous. I don't know what to do or how to do it. I can't even identify the majority of my emotions. I can't name them or pinpoint how I feel.

Any advice?

I'm sorry to hear you are struggling so much. I can relate to much of what you have said (wife being upset, stressing over having relapsed, worried about reaching out to t...).
Was there more to the sh than just sh last time? or does T just take it *very* seriously? I know I have freaked out about telling T's in the past, but generally, once my risk-level was assessed, being trapped was no longer an issue. I guess it goes with what the cutting means to you. for me, it's generally a way to gain internal control when things feel out of control, it's a release on all the pressure.
Maybe you could reach out to T and tell her you are stressing, and the extent of that stressing? Did you guys talk about how her reaction last time made you feel? Could you bring it up this time with her (or bring it up again)? Even if it's just starting the conversation around being anxious to tell her something, and not really knowing how to describe it...

Also, you did not fail. you did really good for a long time, and you hit a bump in the road. right now it's just a bump in the road, not a splat onto the pavement...