Arjun is in a very critical situation here.
Why did Arjun agree to marry Ovi?
He should have just ignored Purvi's request.
He should have stopped his marriage with Purvi and moved ahead.
Ovi asked Purvi to leave Arjun. Purvi should have done this. all three should remained single.
This marriage drama looks stupid.
No one is happy.
Purvi and Arjun became mahan sacrificing their love.
Till now Arjun and Purvi shown respecting relationship. For the sake of family and his promise (whatever) Arjun tries to stay as a husband to Ovi. This Ovi with her confused thoughts and Punni's evil inputs destroying her own relationship now.
now this pregnancy track adds more stupidity. Keeping Ovi's past incident there is a possiblity for Ovi getting tricked by Romil. When a girl thinks more about herself and doubts everyone around her husband, its easy for a thrid person to divert her mind in a wrong direction. Ovi surely with conscious won't have any puhsical contact with Romil, but possible do so in her desperate situation in her unconscious state.
Later she will act normal and claim that baby's father is Arjun. Ovi will do anything to keep Arjun with her. Seeing Arjun's soft nature towards Ovi, surely Arjun won't reveal the truth about baby to family members. Already she is hiding the deal and balming Arjun for meeting Purvi in random places. this shows Ovi's nature.
surely Ovi's child will get Arjun's name as father. till now one character of Ovi is revealed very clearly. Ovi does anything right or wrong. at the end she claims that she did for Arjun. she doesn't care her ways hurts anyone around her or not. She wants Arjun to be with her. she wants to be his wife.
Arjun having physical contact with Ovi can be possible if she gives too much drink to him to fulfill her happiness. In that case Arjun's respect on Ovi may go down but no harm in the society. For the sake of child he will be staying as her husband or fall in love with her later. then its victory to Ovi but it can't be considered PR. Only Archu - Manav relationship is PR.
Arjun on his own having physical contact with Ovi will be too early. He is still not out of his pain. he can have and there is no sin doing so but will take little time for a normal man.
Purvi getting pregnant is out of character. she has been shown as a person respecting every single tradition. In that case Purvi having physical contact with Arjun will kill her character.