The importance of learning to live with ones self can never be overemphasized.
Many people never really find peace with who they are; they never even create time or give themselves the opportunity to actually realise what their identity really is and this tells [often negatively] in the romantic relationships they get involved in.
And for those lucky enough to understand themselves and their true identity, there is also a fear that being in a relationship could strip off the core of their person.
Here is the thing about human closeness; when two people share a bond - friendly, parental or romantic - there is a strong possibility that they'll begin to pick from each other's behaviours and rub off on each other.
This probably explains why many married people are said to look like each other after being together for a significant amount of time.
So it is true that in marriages and relationships, you could lose your identity and become overly absorbed in being a couple to the detriment of being your actual self.
Being invested in a relationship is not wrong, but losing yourself in the process is.
You share your life with a partner, you don't give it all up to them or for them.
One way to ensure that you retain yourself in a relationship, according to Funmi Iyanda, is to keep your friends close even after you get into a relationship.
Being in a relationship is not a call to isolation or reclusiveness from the 'outside world and as a matter of fact, a partner that tries to keep you away from your prior great [non-romantic] relationships is not ideal.
Another way is to keep doing the things that were fun to you while you were single. Truth is, those things probably attracted your partner to you.
Funmi Iyanda adds in the 5th episode of her Youtube Vlog "Ask Funmi" that it is best to also let there be gaps in one's relationship.
To achieve this, one needs to have some source of income and stay in charge of his/her resources.
She gives a detailed explanation in the video below: