Merizsa, I suppose you could say that since the grounds have whatever degree of nitrogen in them, such addition to plants generally, would do OK by them.
You have been adding coffee grounds for two months...but then how much is that, how often in those two months and how much volume of soil does the plants so affected have.

Coffee grounds are indeed sligtly acidic and if you were to take the coffee waste from a STARBUCKS on a daily basis and gave that to your garden plants that surely would amount to a hefty giving of nitrogen.
But, giving an amount such as that to one or two houseplants I've gotta think it would be overkill.

Coffee grounds do affect soil's acidity and mixed with the soil can add benefit. Now you have to just measure how much, how often. what you don't want to do is upset the balance of soil that is the medium the roots are deriving nutrition from.
Dilute with water for a gentle, liquid fertilizer. Use about a half-pound of used grounds in a five-gallon bucket of water. It would be best to let this container sit for a time to garner room temperature.
Tea leaves can be said has the same benefit.
Tea bags, once used, can be used again in diluted form to give a tonic to houseplants. Tea bags can be allowed to dry and then be broken open and spread on the soil surface and each time you water, it gives a diluted feeding.

One thing dried coffee grounds does do, it makes slugs, snails and gnats think twice about walking over it.

You might take this too far. We know that nitrogen if given in too heavy an amount can cause plants to grow well....but can upset the plant's wish to create flowering.
Same with outdoor plants that are given too much nitrogen...sometimes by careless use of lawn fertilizer around gardens that causes an increased take-up of nitrogen and deprives the plant's wish for phosphurus.
Phosphurus is the element that will increase flowering.

Coffee grounds are a decent source of nutrients and Starbucks has an analyses posted on the web,
What's in Coffee Grounds?
Nitrogen 1.45% Calcium 389ug/g
Phosphorus ND ug/g
Magnesium 448ug/g
Potassium 1204 ug/g
Sulfur high ug/g
Notes: ND= indicates sample is below detection limit
Ug/g= microgram/gram

Information provided in part by: www.starbucks.com

Research also shows that coffee grounds will have no significant affect on your soils pH, to possibly make some change you would need to add tons at one time and even then it is doubtful that any vegetative waste material would affect how many free radical ions are running around in your soil.