Is there a concession allowing one who is newly married not to pray in congregation?

There is a great deal of evidence which shows that it is
obligatory for men to pray in congregation as you will see discussed in
detail in the answer to question no.
120. We do not know of any evidence
that suggests that a newly married man is allowed not to pray in
congregation, apart from a few fuqaha’ who stated that the one who is
waiting for his bride to be brought to him is excused from praying in
congregation. 

Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) was
asked about his opinion on this and he said: We think that the views of the
scholars may include those that are wrong and those that are right. What is
essential is to refer to the Qur’aan and Sunnah. 

Secondly: 

The scholars who said this were speaking about something that
they used to do, whereby it was the man who received the bride, and the
bride did not receive the man. The man would be in his house and his wife
would be brought to him, and this was an excuse for not praying in
congregation, because if he went and prayed in the mosque, he would not be
focusing on his prayer because his mind would be distracted, and the Prophet
(peace and blessings of Allaah be upon him) said: “There is no prayer
when food is ready.” Ibn ‘Umar (may Allaah be pleased with him) would hear
the imam reciting whilst he was eating dinner and he would not get up to
pray until he had finished eating. If a man is excused for not attending
prayer in congregation in this case, then the one who is waiting for his
bride to be brought to him is more distracted, so the excuse is obvious. But
the custom of people nowadays in our country is different from that; the
groom comes to the bride where she is, so it is up to him and he has no
excuse for not praying in congregation. End quote. 

From As’ilah al-Liqa’ al-Shahri (29). 

With regard to the wedding being an excuse for not praying in
congregation at all, although some of the fuqaha’ have mentioned it, there
is no saheeh evidence for that. Shaykh Ibn ‘Uthaymeen (may Allaah have mercy
on him) was asked about someone who did not pray Fajr on the morning of his
wedding and his answer was: The groom has to pray Fajr in congregation and
not fail to pray in congregation with no legitimate excuse. End quote. 

From As’ilah al-Liqa’ al-Shahri (29). 

Secondly: 

What the questioner is asking about – a newly married man not
praying in congregation for a week – is something that some people think is
Sunnah. Perhaps they understood this from the words of Anas (may Allaah be
pleased with him): It is Sunnah to stay with a virgin for seven (days).
Agreed upon – this version was narrated by Muslim (1461). 

But the meaning is not as these people understand it, that he
should stay with her for seven days and not go out of the house or pray in
congregation in the mosque.  

Rather what it means is that if he marries a virgin and he
has another wife, he should allocate seven nights to the virgin, just for
her, then after that he should give each wife a night in turn. 

This is narrated from Anas (may Allaah be pleased with him)
in the hadeeth quoted above, which was narrated by al-Bukhaari (5214) and
Muslim (1461): It is Sunnah, if a man marries a virgin when he already has a
wife who was previously-married, to stay with her for seven days, then
divide his time (between his wives). And if he marries a previously-married
woman when he already has a wife who was a virgin, he should stay with her
for three days and then divide his time.  

From this version it is clear that what Anas meant was that
he should stay with a virgin for seven days, i.e. give her seven days just
for her, then start to divide his time between her and his other wives. 

And Allaah knows best.