Let us consider the plan Thanos said or at-least what I heard:

He wanted to eradicate half of everyone from every planet.

Now let us consider Thanos himself... he is the last surviving Titan from the planet well Titan. So he can be justified for surviving since he is the last Titan and half of 1 rounding-off is well one...

From the director's surprise visit to Iowa City high school:

Thanos was apparently a part of selection and he happened to be in living end...

You can ask if he allowed himself to be apart of that random process. He does have a very interesting look on his face. When we come back to him after the snap before he disappears, a look of surprise.

For a utilitarian, ensuring one's survival is often justifiable as a "altruistic" act; if one believes that one's morality is superior to others', then remaining alive to enact it is good.

It seems to me that there are two obvious questions that were never addressed in the film:

How does killing half the population address overpopulation? Eventually, the population will rebound. What then? Will Thanos just keep engaging in occasional cullings?

Given the vast power that the stones give him, does Thanos not have anything he can do to improve quality of life other than killing half the population?

Both of these questions touch on yours. If Thanos is planning on doing future cullings, then obviously he has to stay alive to do so. And if Thanos has some plan beyond the culling, then again he has to stay alive for that. Even if he doesn't have any further plan, he does have to worry about what will happen with the stones if he dies, so he can justify keeping himself alive to make sure the stones aren't "misused".

On top of that, as Thanos' justification was that there were too many people for the available resources, that doesn't apply to him; presumably with the stones, he can provide himself with whatever resources he needs without reducing the amount of resources available for others.

Thanos apparently intended to live

In his speech to Doctor Strange, Thanos refers to the imminent victims of the 'Snap' as 'they', while he envisions himself remaining to enjoy the universal prosperity that Thanos imagines will result from his plan.

THANOS: "With all six Stones, I could simply snap my fingers. They would all cease to exist. I call that... mercy."

STRANGE: "And then what?"

THANOS: "I finally rest. And watch the sun rise on a grateful universe. The hardest choices require the strongest wills."

EDIT: The above answer was also proposed and accepted here.

... and he will need to guard the Time Stone so that what was done cannot be undone

If Thanos includes himself in the 'snap', then it is possible that the Infinity Gems might fall into the hands of one with the power and skill to reverse the effects of the 'snap' on the universe, especially if they have the Time Stone. Indeed, Thanos' actions in Avengers: Endgame bear this out; not long after the 'snap', he destroys all the Infinity Stones, at great risk to himself. He correctly anticipates that Earth's heroes will come after him in an attempt to wrest the gauntlet from him and reverse the 'snap'.

Thanos needed to survive in order to subsequently destroy the Infinity Stones. If he had disappeared in the snap then someone else would simply have put on the gauntlet and brought everyone back.

Therefore he must have planned to survive so he could remove the only way to undo the snap afterwards. Obviously he did not count on his opponents going back in time to frustrate him.

Comics-based Answer

I would say yes, he probably was committed, and that is how to interpret him in the movies, because, in the comics, he is ultimately committed to his goals, even to the point of death. He most likely included himself as a possibility in the Decimation, there was probably a 50% chance of him dying.

However, in the comics, dying is not a big deal for Thanos. He loved (currently I think he is fascinated by Oblivion, as per Civil War II; I'm not sure how his most recent death has changed his view) Death, the Abstract personification of death, and dying simply brings him to her. She in turn "spurns" him, meaning he does not stay dead for long. I put spurns in quotes because it seems that Marvel's current vision of Death and Thanos' relationship is that she is using him; he is essentially acting as her champion and avatar, bringing death to the cosmos, and his love for her is a convenient tool.

So, to say he would die for his goals is not saying much. But he is generally considered a man of his word (though Galactus once called him a renowned liar, so Marvel's writers are not all in the same boat on this) and a man with a sense of honour, twisted as it may be.

From the sense of relieve that he seems to feel after he kills half of the universe, it makes me think that he wasn't sure at all of him surviving. I think he was really committed.

[ And from what other people has answered, it makes no sense that what we see in the movie is him erasing half of everyone in every planet.

Not many humans would die. In a recent study it was calculated that the total weight of the earth's insects is about 17 times greater than the total weight of humans on earth. And insects are much smaller, so just think about it...

It would make much more sense if what we see is the eradication of half of each specie on each planet. And more sense in his ideal, as usually communities are formed by individuals of the same specie, and that would duplicate the available resources of most of the communities.]

What Kaito Kid answered is completely true. Mental note: "Don't post on friday afternoon, better after the weekend".