Is it selfish of you... is it cheating on your wife if you purposely seek ego death? Do you sleep every night? Is sleeping cheating on your wife? Sleep is a version of ego death that is embraced by the ego. Ego death through psychedelics is not really KILLING your ego. It's more like putting it in a time out. The ego doesn't like this. It will fight and you must surrender or you are going to have a rough time.
I have a theory. It comes from dealing with suicidal ideation on a regular basis and having those suicidal thoughts, reliably put away for awhile by psychedelics. I see a drastic reduction in depression and anxiety after a full on psychedelic experience. Especially if I achieve ego death. Which is very common for me, opposed to what Zikzak says. I think if you practice surrendering, it gets easier and easier.
Here's my idea: When someone is walking around with their brain constantly saying to them: "Kill yourself. Kill yourself. Kill yourself." What it is really saying is: ""Kill THE self. Kill THE self." People in modern society have largely lost the knowledge of the methods for creating ego death on demand. That's why suicide is so common. Just like our devices, we need reboots and de-frags on occasion. Some more often than others.
You are not going to break through and come back as, literally a different person, in a different universe, and if you are, it may already be happening every time you go to sleep and wake up. Or every time you blink. And the same thing is happening to your wife. I seriously doubt that this is how things work. If you are truly worried that you will come back from a breakthrough as a person who is so different that your wife wouldn't recognize you or want to be with you, you may want to consider not doing dmt. I don't know the nature of your psychosis. Dmt could be a bad thing for you.
If it was a transient psychosis caused by chemicals or a physical health problem, and dmt isn't making you delusional, consider doing it with your wife. Multiverse polyamory. If you do continue to use dmt, have a support group. Tell people about your experiences and the ideas you are having. Friends who aren't tripping can be very helpful. they can tell you if you are losing your shit. If you are believing ridiculous or dangerous stuff.
Good luck to you. Talk to your wife. She's your wife. That's what she's there for.