Which makes relationship (like mother-son or husband-wife)? The body or the Atma? Is there any role of Paramatman in this regard ?
Atma or the soul apparently doesn't create these relations. Because it continues to exist even after death. But body ceases to exist then.
धर्मं शनैः सञ्चिनुयाद् वल्मीकमिव पुत्तिकाः ।
परलोकसहायार्थं सर्वभूतान्यपीडयन् ॥ २३८
Manu Smriti 4.238. Giving no pain to any creature, let him slowly accumulate spiritual merit, for the sake (of acquiring) a companion to the next world, just as the white ant (gradually raises its) hill.
नामुत्र हि सहायार्थं पिता माता च तिष्ठतः ।
न पुत्रदारं न ज्ञातिर्धर्मस्तिष्ठति केवलः ॥ २३९
Manu Smriti 4.239. For in the next world neither father, nor mother, nor wife, nor sons, nor relations stay to be his companions; spiritual merit alone remains (with him).
Now, in the next world our body does not exist but the soul does. So, these relations exist till the point the body exists. So, obviously the soul is not making these relations.
However, it is to be noted that there are 3 kinds of bodies viz: Sthula Sarira (the Gross body), Sukshma Sarira (Subtle body) and the ParA Sarira or KArana Sarira (or the Supreme body).
And, among these 3 bodies, only the gross body dissolves on death. The subtle body continue to exist even after death. It is said to exist till Moksha happens. The Supreme body of course is ever existent.
In my answer, i have taken "body" to mean the "gross body".
Is there any role of Paramatman in this regard ?
No it seems. Lord Shiva says:
Dehah karmAtmakah proktastattad dehe pratishtitham ||
KarmayogAnurupena nirmAnam vidhirAdishet |
CharAcharamidam devi sarvvam karmAtmakam priye ||
MAtA karma pitA karma karmaiva paramo guruh |
Swargam vA narakam vApi karmanaiva labhennarah ||
O Goddess, O Beloved, the body is known to be the manifestation of karma and all such karmas are established in the body itself. The Almighty gives orders to craft bodies as per karmas. And this whole movable-immovable world is nothing but a manifestation of karma. The mother is [an outcome of] karma, the father is karma, the Supreme Guru is also karma. One obtains heaven and hell by karma only.
The purport of the above verses is that one receives parents depending on one's own karma. So, apparently the ParamAtman does not have any role to play. But this topic is rather philosophical in nature and further arguments can be given from both sides. I am not sure if reaching a definitive conclusion is possible or not.
Hypothetical. The answer is found in polarity.
In any relationship where there is sexual attraction and deep intimate connection, you’ll find the power of opposite energies in every moment of life from childhood to till death. We have intense physical chemistry with those who have an opposite energy to our own. Whether masculine or feminine, this energy is not gender-based. Every man and woman has varying degrees of both masculine and feminine energy, but one is a natural dominant force inside you.
Polarity is like a light switch; it can be turned on in a moment. When it comes to love and passion, practice and cultivate your natural energy. Embody it, Embrace it and it will energize your relationship.