Learn Hardcore Spanish (Spain): Mi hermano prefiere seguir soltero y viajar antes de pensar en casarse. - My brother prefers to stay single and travel before thinking about getting married.

In Spanish, when you have a verb of preference, desire, intention, or start/stop/continue followed by another action, the second verb is usually in the infinitive.

prefiere seguir = he prefers to continue
prefiere … viajar = he prefers to travel
antes de pensar = before thinking
pensar en casarse = to think about getting married

Only the first main verb (prefiere) is conjugated to match the subject (mi hermano). The actions that are “dependent” on that main verb stay in the infinitive. This is very normal Spanish structure.

Why is it seguir soltero and not seguir siendo soltero?

Both are possible, but seguir soltero is shorter and completely natural.

seguir soltero literally: to remain single / to stay single
Here seguir works like “to go on being / to remain”, and soltero is an adjective describing mi hermano.
seguir siendo soltero is more explicit (to continue being single), but it sounds a bit heavier and is usually only used if you really want to emphasize the being.

In everyday Spanish, seguir + adjective (seguir soltero, seguir feliz, seguir cansado) is very common and idiomatic.

Is soltero a noun (a bachelor) or an adjective (single) here?

Here soltero works as an adjective describing mi hermano.

Mi hermano está soltero. – My brother is single.
Prefiere seguir soltero. – He prefers to remain single.

It can also be used as a noun:

Es un soltero empedernido. – He’s a confirmed bachelor.

In this sentence, because it follows seguir and is directly linked to mi hermano, it is functioning adjectivally: he prefers to remain in the state of being single.

Why is it viajar (an infinitive) and not something like de viaje?

Viajar is a verb (to travel), and it’s parallel to seguir soltero as another activity he prefers:

prefiere seguir soltero y viajar = he prefers to stay single and (to) travel

De viaje is a set phrase that means away on a trip:

Está de viaje. – He is away on a trip.

If we used de viaje, we’d lose the clear verb structure that matches prefiere. With prefiere, Spanish expects another verb (infinitive), so viajar is the natural choice.

What exactly does antes de do here? Does it mean “before” in time or “rather than”?

In this sentence, antes de is mainly temporal: it relates to time/order of life decisions.

viajar antes de pensar en casarse
= to travel before (he even starts) thinking about getting married

So the idea is: first travel, then much later think about marriage.

It doesn’t mean “rather than” (i.e. instead of); that would be more like:

prefiere viajar en lugar de casarse – he prefers to travel instead of getting married.

Here, the sentence suggests marriage is something for later, not something completely rejected.

Why is it antes de + infinitive instead of antes de que + subjunctive?

Both structures exist, but they are used differently:

antes de + infinitive
Used when the subject of both actions is the same:
- Mi hermano prefiere viajar antes de pensar en casarse.
  Subject of viajar and pensar (en casarse) = mi hermano.
antes de que + subjunctive
Used when the subject is different (or when you want a full clause):
- Prefiero hablar contigo antes de que te vayas.
  I (yo) prefer to speak / you (tú) leave.

In your sentence, because the same person is doing all the actions, Spanish naturally uses antes de + infinitive.

Why is it pensar en casarse and not pensar casarse or pensar de casarse?

The verb pensar changes preposition depending on the meaning:

pensar en = to think about (something)
- pienso en ti, pensar en casarse
pensar de = to think of / to have an opinion about
- ¿Qué piensas de esta película? – What do you think of this film?
pensar + infinitive (without preposition) = to plan to / intend to
- Pienso casarme el año que viene. – I’m planning to get married next year.

In your sentence, the meaning is “to think about (the idea of) getting married”, so Spanish needs pensar en:

pensar en casarse – to think about getting married

Why is casarse reflexive here? We just say “to marry / to get married” in English.

In Spanish, the usual way to say “to get married” is casarse, a reflexive verb.

casar alone = to marry someone else (e.g. what a priest or judge does)
casarse = to marry / get married (from the person’s own viewpoint)

Examples:

Quiero casarme. – I want to get married.
Se casan en junio. – They’re getting married in June.

In pensar en casarse, the reflexive se is part of the infinitive casarse.
It will refer to the subject mi hermano even though it isn’t repeated:

Mi hermano prefiere … antes de pensar en casarse.
= … before thinking about getting married (himself).

Why is the reflexive pronoun se attached to casarse and not written separately?

In Spanish, with infinitives, gerunds, and affirmative commands, reflexive and object pronouns often attach to the end of the verb:

Infinitive: casarse, levantarse
Gerund: casándose, levantándose
Affirmative command: cásate, levántate

So:

pensar en casarse = to think about getting married
You wouldn’t normally say pensar en se casar (that’s incorrect).

In conjugated forms, the pronoun goes before the verb:

Se casa mañana. – He/she’s getting married tomorrow.

Does antes de pensar en casarse go with seguir soltero too, or only with viajar?

Logically, it applies to the whole preference: He prefers to stay single and travel before thinking about getting married.

Grammatically:

prefiere [seguir soltero y viajar] [antes de pensar en casarse]

So the time frame “before thinking about getting married” colors the two activities together:
he wants to remain single and travel first, and only later think about marriage.

Could we change the word order, like Mi hermano prefiere viajar y seguir soltero antes de pensar en casarse?

Yes, that’s perfectly possible and correct:

Mi hermano prefiere viajar y seguir soltero antes de pensar en casarse.

The meaning is essentially the same. Changing the order to:

seguir soltero y viajar
viajar y seguir soltero

only slightly changes the emphasis (what you mention first), but not the basic idea: he prefers both staying single and traveling, before considering marriage.

Why is it soltero and not soltera?

Because the noun hermano is masculine. Adjectives in Spanish must agree in gender and number with the noun they describe:

Mi hermano prefiere seguir soltero. – masculine singular
Mi hermana prefiere seguir soltera. – feminine singular
Mis hermanos prefieren seguir solteros. – masculine plural or mixed group
Mis hermanas prefieren seguir solteras. – feminine plural

So here soltero matches mi hermano.

Is there any difference between soltero and English “single”, especially in Spain?

Yes, there’s a nuance:

soltero in Spain usually means unmarried (not legally married).
A soltero might or might not have a boyfriend/girlfriend/partner.
English “single” often suggests not in a romantic relationship.

So:

A person living with a partner but not married is soltero (not casado) in Spanish, but in English you probably wouldn’t call them “single”.

In this context, seguir soltero = to remain unmarried, with a strong implication of not committing to marriage yet.

Why is it Mi hermano and not just Hermano or El hermano?

In Spanish, to talk about your own relative, you usually use a possessive adjective:

Mi hermano, mi madre, mis abuelos, etc.

El hermano usually means the brother in a more general or external sense (e.g. “the brother of X” or “the brother in that story”), not clearly my brother.

You could drop mi in a very specific context where it’s already obvious you’re talking about your brother, but normally you’d say mi hermano to make it clear.