Yeah totally!! id say they could have any kind of relationship! anyone who has a relationship with a deltude just has to respect their boundaries! usually stuff like making sure to not look at the deltude if their suit is ripped, or to give the deltude space when they need it. Deltudes can get emotionally exhausted after periods of being around others. like an introvert, but with more anger issues. so just more care and work is needed to sustain a relationship with one. but its totally possible!
other than that general stuff, its really up to the owners to decide how they want to do things! what i provide is just general species behaviors that's shared between all of them. but each individual is different and has different levels of tolerance.