They already have, barely. (Wow. I meant leave a quick two sentence comment but got caught up in their feelings...)
They both lost their virginity to each other in
Chapter 54 "Gyaru-Sen and The Holy Night".
Consummation occurred on Pages 7 through 10, with the
Instant Shot leaving Nezu feeling
miserable and inadequate. Suzu-nee's defloration pain face and her soothing words to Nezu about it confirm she was still a virgin. On
Page 15 she was ready to give him another round, showing that this wasn't going to be a one-time thing, until the
Cock Block Party arrived. (At the end of the previous chapter we see that she equipped him with the
Legendary Protection so at least he doesn't have to worry about one-stroke child support.)
We have seen several times including Ch 54 that she does love him. I just wish she hadn't become so sadistic (maybe dominating is a better word) while they were apart. Since she was still a virgin to this point it was probably in reaction to the emotional damage from his
hurtful and deeply-regretted confused reaction to her bathing him instead of abuse by some other man (insert link to some Nhentai page...). Hopefully they can heal each other to become more normal instead of him ending up collared and her holding the leash.
All we've seen to show that Suzu-nee is supposed to be "experienced" is her
flippant answer to the student's question about how many men she's slept with (which tortured poor Nezu). The rest of it is what is inferred from her appearance and behavior (which tortured poor Nezu). The cucked feeling from thinking that other men had and corrupted his First and Only Love tortured poor Nezu. (Did I mention that poor Nezu must have felt tortured? Nezu felt he was being punished in Hell for his sin of hurting Suzu-nee as he did.)