Monks should marry because they are good people and who else should marry but good people? Should bad people marry? No, good people should marry as they are better people. And, obviously there are no better good people than monks. I think the monks in Japan would agree with this theory.
May all beings understand the dhamma and not follow this theory. 
In Thailand traditionally it was expected that a man should become a monk for a short period. After disrobing he would be seen as a suitable candidate for marriage.
I don`t see that recommended in the texts though.
Yeah, it’s not necessary to become a monk for a short period but in thailand it sort of became a tradition and I have seen that sometimes people become monks for a short period because of vanity and that clearly can’t be good. Sometimes it’s used just as a vanity point and nothing else. I think getting the experience of how a monk lives for a while can be beneficial but it’s not necessary at all for laypeople who want to get married. And, I personally think that there’s a problem with this tradition and that problem is that because most people would agree that a man will be seen as a suitable candidate after disrobing, it would create a surplus of ‘monks’ who will not become monks for the right reasons and might even misuse their status as a ‘monk’ just to get married or some other reasons. So, I think that monkhood should be encouraged for other reasons and not because one is seen as more suitable for marriage that way because that just pollutes the dhamma and is in no way good for the sasana, in my honest opinion. However, your detailed outlook on this would be greatly appreciated, @RobertK
You make some good points in your post but there are probably other dimensions to it.
I have never been a monk so probably @bksubhuti or the other bhikkhu members would understand this better.
@Trobinson465 was a monk for a period of time so would also have a useful perspective.
Monks who disrobe for women to marry rarely last in marriage.
All that said. A monastic friend of mine with 25 years disrobed. He later got married. He kept his precepts (as I describe and define them) for 2 years until he got married . So this was an outlier.
In this rate case, he is a good catch for his wife. Plus he is wealthy from his family’s fortune. He has lived a blessed life. I wish him well and miss him.
If most monks can’t even fully commit to the holy life then I don’t think the buddha sasana with last that long. If they can’t do that it’s not gonna happen. Will most be able to commit to the holy life for the rest of their life? No, probably not. It doesn’t inspire confidence in the current sangha and the problem is that they later get married. Which is why not me but girls have said that, ‘Monks become monks to get married.’ They are of course slandering the current sangha and those are girls, not me. If this continues, I have no doubt the sasana will be gone.
Sāsana is very fragile, but it is dependent on the influx of new monks to survive. Rūpa itself is always perishing. However, new rūpa arises quickly in the same proximity of the perished rūpa.
The populations of towns cities regions and countries, even the world are like this. People die everyday. Another group went to see an autopsy today. The person was 51 years old and died by a snake bite yesterday. But there was surely quite a number of new born babies today too.
Temporary ordinations are fine. I know a monk who ordained for 45 days and stayed 13 years. At one point his father, brother and two daughters were ordained. The father is still a monk (I think he is still alive). So it is all good.
Even though temporary ordinations are totally fine as it’s not required that when one ordains one must ordain for life. But, the thing is that most monks are gonna be monks for years or months or a few weeks but after some time they disrobe to get married. If they can’t attain the path and marry a girl later then that way it’s not gonna work out, the dhamma will not be properly established. And, a girl said this about that, ‘We can’t even go to monasteries anymore, the monks see us and want to marry us, saying that they will disrobe for our hand in marriage.’ If this goes on, it’s not gonna work out for sure.
Yes, the short term ordination thing is one of the iconic attributes of Thai Buddhism actually. Its certainly allowed as this happened in the Buddha’s time on occasion and theres clearly no rule against temporary ordination laid out in the vinaya. Like with anything in this imperfect world, i think there are some tradeoffs.
I do agree the tradition has a few drawbacks, people ordaining for the wrong reasons. Having been a monk temporarily before I’ve encountered people who were just ordaining because thier family or future wife’s family made them (i havent really seen people do it out of vanity tho). And sometimes they behave improperly and accumulate bad kamma since they arent there out of faith and see it as just some kind of thing to get over with. Also not the best kind of people to be ordaining with if you’re one of the more serious types in the cohort.
I do think its a useful tradition tho overall. Just trying the monk/ascetic life can be very beneficial, textual knowledge is useful and very much necessary to get started but it can’t take you deeper. It is only thru serious Dhamma practice can you get a deeper understanding of impermenance, suffering and non-self, and what better way to do serious practice than to be a monk? I also dont think of it as all or nothing, while its preferable a monk gets a deeper understanding of the Dhamma and stay a monk until final liberation, even just experiencing the deeper understanding of the Dhamma in a temporary ordination and then leaving is better than never experiencing it at all.
And like with all things in Classical Theravada, you also have to think of it on a multiple lifetime scale as well. Just developing an affinity for monkhood/ascetic life even temporarily is good for your nekhamma parami and increases your chances of taking on the role in future lives.
And like Bhikkhu Subhuti said, temporary ordination serves as a great gateway into permenent monkhood. Probably the majority of Thai monks ive encountered who ordain for life decided they wanted to after ordaining temporarily. I know a few people i ordained with who ordained temporarily and then decided to stay permenently, and even one who ordained temporarily, decided he wanted to stay permanently, disrobed, got his life responsibilities in order, and then came back the next year with the intent of ordaining and staying a monk for life.
The temporary ordination tradition of Thailand isnt perfect but i think its a net positive from what ive seen as someone who has tried it and experienced its various complexities. I think its certainly preferable to the opposite extreme seen in Sri Lanka where there is a stigma against monks ever disrobing, which i think causes another set of bigger problems, such as monks who want to disrobe but won’t due to stigma and scaring off people on the margins who think they have to commit to it to life. Historically, Sri Lanka has even had to invite monks from Thailand to revive thier bhikkhu order due to lack of ordinands. This is purely speculation but given how many monks in Thailand ive met who decided to ordain for life after trying temporary ordination, I’d say the ordination cultures of each of the countries probably played a role in why it ended up that way. Of the two extremes of ordination culture found within Thailand and Sri Lanka, i think the Thai temporary ordination culture is certainly the more beneficial one.