Parenting an ADHD child has put such a strain on my marriage :(

I'm posting here in the hope that there are others out there with a similar experience.

I've been married for 14 years, and am a parent of a 10 year old girl who got diagnosed with ADHD when she was about 5. Ever since, the relationship with my wife has gone gradually down hill, and now I'm at the point that I'm going to move out for a while. This has not been an easy decision, but I'm really at my wits end, and don't see any other alternatives.

I've grown more and more resentful over the years, as it seems that everything in my family always revolves around my daughter. My wife and I have really lost sight of each other and our own needs, which is an insight I've gained after several months of marriage counseling. On top of this, I was really depressed when going into counseling, so I was prescribed anti-depressants. This has really helped me to become less agitated, but still, the situation at home has not stopped from sliding downwards.

It's still hard for me to be patient with my daughter, and I get jealous when I see kids her own age being much more independent than her. And I know it's not her fault.  I continue to be resentful towards my wife, because I feel like she's always put my daughter and her special needs before me. Then came the realization that I've put my very own ambitions and aspirations in life on the back burner in the past couple of years, and it is killing me inside. Perhaps I'm in midlife crisis as a result.

So now I'm moving out for a while, very much with mixed feelings. There is part relief, and there is part guilt. I want my marriage to get back to the way it was, but I'm not able to. I'm not even sure if this is the right decision, and I'm scared my wife will think I'm abandoning her. But I feel like I need space and time to be on my own for a while to sort things out.

I'd greatly appreciate any feedback from parents who've been in the same boat.