I guess I had my first boyfriend about 15 or so.

我想我有第一个男友时是十五岁左右。

youdao

I'd stopped seeing my girlfriend and Lucy had also split up from her first boyfriend.

我不再和我的女朋友见面，露西也和她的初恋男友分了手。

youdao

I would always compare all my lovers to my first boyfriend, because he was the sweetest in my mind.

我总会把自己所有的情人跟第一位男友做比较，因为在我看来他是最完美、最善解人意的。

youdao

She became involved in prostitution at the insistence of a former boyfriend, who beat her,and forced her to sell her body the first night they arrived.

VOA: standard.2010.02.23

The first example I can think of is if, let's say your boyfriend or girlfriend has just acted outrageously.

我想到的第一个例子是，假设你的男友或女友突然表现得很蛮横。

I can't help but 课堂 - SpeakingMax英语口语达人

And then, when I had my first boyfriend, I realized maybe it's not for me.

CNN: For Better Or For Worse

Within the first month of going raw, she had her first boyfriend in more than five years.

CNN: Woman goes raw, loses more than half herself

She had come to a point in her life of getting through her low self-esteem and was happy in having her first boyfriend.

BBC: NEWS | UK | Scotland | 'My little mentor lives always'