He wants to limit having children because he is poor

Allah says (interpretation of the meanings)

“And no moving (living) creature is there on earth but its provision is due from Allah” [Hood 11:6]

“And so many a moving (living) creature carries not its own provision! Allah provides for it and for you. And He is the All‑Hearer, the All‑Knower” [al-‘Ankaboot 29:60]

“Verily, Allah is the All‑Provider, Owner of Power, the Most Strong” [al-Dhaariyaat 51:58]

“so seek your provision from Allah (Alone), and worship Him (Alone), and be grateful to Him”

[al-‘Ankaboot 29:17]

Allah condemned the people of the Jaahiliyyah who killed their children for fear of poverty, and He forbade doing what they did. Allah says (interpretation of the meaning):

“And kill not your children for fear of poverty. We shall provide for them as well as for you. Surely, the killing of them is a great sin” [al-Israa’ 17:31]

Allah has commanded His slaves to put their trust in Him in all their affairs, and He is Sufficient for those who put their trust in Him. Allah says (interpretation of the meaning):

“and put your trust in Allah if you are believers indeed” [al-Maa’idah 5:23]

“And whosoever puts his trust in Allah, then He will suffice him” [al-Talaaq 65:3].

So you have to put your trust in your Lord and believe that He will provide for you and your children. Do not let the fear of poverty prevent you from seeking to have children, for Allah has guaranteed provision for all. By not wanting children for fear of poverty, you are imitating the people of the Jaahiliyyah.

You should also note that taking out loans with interest is ribaa (usury), for which Allah issues the warning of a painful torment. It is one of the seven sins which condemn a person to Hell. The Prophet (peace and blessings of Allah be upon him) said: “Avoid the seven sins  which condemn a person to Hell…[which include] consuming ribaa.” And he (peace and blessings of Allah be upon him) said: “Allah has cursed the one who consumes ribaa, the one who pays it…” Consumption of ribaa is one of the greatest causes of poverty and loss of blessings, as Allah says (interpretation of the meaning):

“Allah will destroy Ribaa and will give increase for Sadaqaat (deeds of charity, alms)” [al-Baqarah 2:276]

I think that you do not know the ruling on interest-based loans. So seeks Allah’s forgiveness for what is in the past, and do not do it again. Wait for your Lord to grant you a way out and seek provision from Him. Put your trust in Him for Allah loves those who put their trust in Him.