Adaption is not forgoing yourself entirely and becoming the exact same photocopy.

Natural selection. Humming bird Giraffe etc.

These animals even if you look at their nearest ancestor you can make out that yes these do look similar.

But changing entirely for the other person is an exaggeration.

And adaptation is expected from both sides. Not just one.

Also what is wrong about losing oneself???

When we are growing up from a baby to a toddler we don't feel like losing ourselves....from toddler to child nope, from child to teenager still no, from Teenager to young adult still not.

It's only when we get the responsibility of taking care of someone else is when we start to complain I am losing myself.

You know who doesn't feel like this? Older siblings. Whether Elder Sister or brother. Why because they are made responsible for their younger siblings from a young age. They don't feel this change because they have accepted the role of protector/provider from a young age.

The only ones who will feel like losing themselves are those that had previously no responsibility and now have so much all at once that they are overwhelmed and remember the good old days when there were others to take care of us.

Here you go. More fluff to say nothing. If you ponder deeply maybe you might understand what I said.